I think the time in history that God made Himself most obvious but still hidden was when He entered His creation through the virgin Mary and became Man. During His lifetime that period of time that He walked the earth, even then He never forced upon people who He was so some were able to see, others werent, some only noticed much later yet they were eye witnesses but not all believed, God is humble and meek, even the way He was born into this world was very quietly and humbly in an animals barn not inside a palace with huge celebrations from the town.That sounds like copium. God since he is infinitely powerful could obviously figure out a way to reveal himself in such a way that almost all people would believe and I do not see how it affects free will since he would not be forcing anybody to accept him or worship him once he has revealed himself.
That also sounds like copium. Why would good play favourites and only give some groups the full revelation and others group only partial revelation? Did he not imbue all groups of men with eqaul innate morality?
I have heard enough instances from people I know or have met of things happening in this world that are beyond the explanation of the physical reality that science can explain but its a huge leap to go from "there is something beyond the physically explainable reality" to "god exists and is the Christian god"
The Magi who were originally from Iran they came to worship Christ the child through the revelation that the stars gave them wether it was astrology or astronomy I dont know for sure but the creation, the cosmos led them to Christ at his birth, this might be a topic you want to research yourself about the Magi how through nature they got the revelation of who Christ was and why they worshipped Him.
Another topic you might want to examine is the physical history or Christ as a historical figure and also why did they Greeks, Romans and the Egyptians abandon their religions to convert to Christianity at that time without anyone pointing a gun to their head.