God has worked directly with or responded directly to people on an individual basis many times in the past––even in New Testament times. There's no reason to assume He cannot and does not do so today whenever He deems it necessary.
2 Chronicles 16:9a
9 For the eyes of the LORD range throughout the earth to strengthen those whose hearts are fully committed to him.
• Enoch: Genesis 5:23-24
[23] So all the days of Enoch were three hundred and sixty-five years. [24] Enoch walked with God; and he was not, for God took him.
• Noah: Genesis 6:8-14
[8] But Noah found favor in the eyes of the LORD.[9] These are the records of the generations of Noah. Noah was a righteous man, blameless in his time; Noah walked with God. [10] Noah became the father of three sons: Shem, Ham, and Japheth.[11] Now the earth was corrupt in the sight of God, and the earth was filled with violence. [12] God looked on the earth, and behold, it was corrupt; for all flesh had corrupted their way upon the earth.[13] Then God said to Noah, “The end of all flesh has come before Me; for the earth is filled with violence because of them; and behold, I am about to destroy them with the earth. [14] “Make for yourself an ark of gopher wood; you shall make the ark with rooms, and shall cover it inside and out with pitch.
• Abraham: Genesis 12:1-3
[1] Now the LORD said to Abram,“Go forth from your country,And from your relatives And from your father's
house,To the land which I will show you;[2] And I will make you a great nation,And I will bless you,And make
your name great;And so you shall be a blessing;[3] And I will bless those who bless you,And the one who curses
you I will curse.And in you all the families of the earth will be blessed.”
[Acts 7:2 appeared to our father Abraham while he was still in Mesopotamia,]
• Melchizedek: Hebrews 7:1-3
[1] For this Melchizedek, king of Salem, priest of the Most High God, who met Abraham as he was returning from the slaughter of the kings and blessed him, [2] to whom also Abraham apportioned a tenth part of all the spoils, was first of all, by the translation of his name, king of righteousness, and then also king of Salem, which is king of peace. [3] Without father, without mother, without genealogy, having neither beginning of days nor end of life, but made like the Son of God, he remains a priest perpetually.
• Moses: Exodus 3:1-6
[1] Now Moses was pasturing the flock of Jethro his father-in-law, the priest of Midian; and he led the flock to the west side of the wilderness and came to Horeb, the mountain of God. [2] The angel of the LORD appeared to him in a blazing fire from the midst of a bush; and he looked, and behold, the bush was burning with fire, yet the bush was not consumed. [3] So Moses said, “I must turn aside now and see this marvelous sight, why the bush is not burned up.” [4] When the LORD saw that he turned aside to look, God called to him from the midst of the bush and said, “Moses, Moses!” And he said, “Here I am.” [5] Then He said, “Do not come near here; remove your sandals from your feet, for the place on which you are standing is holy ground.” [6] He said also, “I am the God of your father, the God of Abraham, the God of Isaac, and the God of Jacob.” Then Moses hid his face, for he was afraid to look at God.
• Job: Job 1:6-9ff
[6] Now there was a day when the sons of God came to present themselves before the LORD, and *Satan also came among them. [7] The LORD said to Satan, “From where do you come?” Then Satan answered the LORD and said, “From roaming about on the earth and walking around on it.” [8] The LORD said to Satan, “Have you considered My servant Job? For there is no one like him on the earth, a blameless and upright man, fearing God and turning away from evil.” [9] Then Satan answered the LORD, “Does Job fear God for nothing?
• Jonah and the people of Nineveh: Jonah 1:1-2
[1] The word of the LORD came to Jonah the son of Amittai saying, [2] “Arise, go to Nineveh the great city and cry against it, for their wickedness has come up before Me.”
• Jethro -Priest of Midian: Exodus 2:15-16ff
[15] When Pharaoh heard of this matter, he tried to kill Moses. But Moses fled from the presence of Pharaoh and settled in the land of Midian, and he sat down by a well.[16] Now the priest of Midian had seven daughters; and they came to draw water and filled the troughs to water their father's flock.
• Balam: Numbers 22:9-13
[9] Then God came to Balaam and said, “Who are these men with you?” [10] Balaam said to God, “Balak the son of Zippor, king of Moab, has sent word to me, [11] ‘Behold, there is a people who came out of Egypt and they cover the surface of the land; now come, curse them for me; perhaps I may be able to fight against them and drive them out.’” [12] God said to Balaam, “Do not go with them; you shall not curse the people, for they are blessed.” [13] So Balaam arose in the morning and said to Balak's leaders, “Go back to your land, for the LORD has refused to let me go with you.”
• Amorites: Genesis 15:16
[12] Now when the sun was going down, a deep sleep fell upon Abram; and behold, terror and great darkness fell upon him. [13] God said to Abram, “Know for certain that your descendants will be strangers in a land that is not theirs, where they will be enslaved and oppressed four hundred years. [14] “But I will also judge the nation whom they will serve, and afterward they will come out with many possessions. [15] “As for you, you shall go to your fathers in peace; you will be buried at a good old age. [16] “Then in the fourth generation they will return here, for the iniquity of the Amorite is not yet complete.”
God indicates He's aware of the evil of the Amorites, but He is going to delay his judgment for four generations.
• One Who Seeks God: God indicated in Isaiah's day that anyone who sought the true God could be saved.
Isaiah 45:22
Look unto me, and be ye saved, all the ends of the earth: for I am God, and there is none else.
• Magi from the East:
Matthew 2:1-22
[1] Now after Jesus was born in Bethlehem of Judea in the days of Herod the king, *magi from the east arrived in Jerusalem, saying, [2] “Where is He who has been born King of the Jews? For we saw His star in the east and have come to worship Him.”
• Cornelius:
Acts 10:1-6
[10:1] Now there was a man at Caesarea named Cornelius, a centurion of what was called the Italian cohort, [2] a devout man and one who feared God with all his household, and gave many alms to the Jewish people and prayed to God continually. [3] About the ninth hour of the day he clearly saw in a vision an angel of God who had just come in and said to him, “Cornelius!” [4] And fixing his gaze on him and being much alarmed, he said, “What is it, Lord?” And he said to him, “Your prayers and alms have ascended as a memorial before God. [5] “Now dispatch some men to Joppa and send for a man named Simon, who is also called Peter; [6] he is staying with a tanner named Simon, whose house is by the sea.”
• People of Macedonia:
Acts 16:9
A vision appeared to Paul in the night: a man of Macedonia was standing and appealing to him, and saying, “Come over to Macedonia and help us.”
• Ethiopian Eunuch:
Acts 8:26-31ff
[26] But an angel of the Lord spoke to Philip saying, “Get up and go south to the road that descends from Jerusalem to Gaza.” (This is a desert road.) [27] So he got up and went; and there was an Ethiopian eunuch, a court official of Candace, queen of the Ethiopians, who was in charge of all her treasure; and he had come to Jerusalem to worship, [28] and he was returning and sitting in his chariot, and was reading the prophet Isaiah. [29] Then the Spirit said to Philip, “Go up and join this chariot.” [30] Philip ran up and heard him reading Isaiah the prophet, and said, “Do you understand what you are reading?” [31] And he said, “Well, how could I, unless someone guides me?” And he invited Philip to come up and sit with him.
• God had people in Corinth unknown to Paul::
Acts 18:9-10
[9] And the Lord said to Paul in the night by a vision, “Do not be afraid any longer , but go on speaking and do not be silent; [10] for I am with you, and no man will attack you in order to harm you, for I have many people in this city.”
Acts 17:26-30
From one man he made every nation of men, that they should inhabit the whole earth; and he determined the times set for them and the exact places where they should live. 27 God did this so that men would seek him and perhaps reach out for him and find him, though he is not far from each one of us.…29 "Therefore since we are God's offspring, we should not think that the divine being is like gold or silver or stone—an image made by man's design and skill. 30 In the past God overlooked such ignorance, but now he commands all people everywhere to repent.
This is God reaching out to individuals. This does not contradict Jesus’ statement that no man comes to the Father but through the Son.
Romans 2:14-16
(Indeed, when Gentiles, who do not have the law, do by nature things required by the law, they are a law for themselves, even though they do not have the law, 15 since they show that the requirements of the law are written on their hearts, their consciences also bearing witness, and their thoughts now accusing, now even defending them.) 16 This will take place on the day when God will judge men's secrets through Jesus Christ, as my gospel declares. "