To Be Completely fair ...
There is no reason you should believe anything I say (or what anyone else says, for that matter). Your challenge, should you decide to accept it, is to research the evidence and decide for yourself.
So kiss that "confirmation bias" goodbye and get as much material on subjects that interest you as you can. Confirmation bias is where one has already made up their minds about something and accepts only the information that tends to support their view. To me, wisdom is about collecting all the different viewpoints. That way you have the best chance of coming across the right answer. From there ... let your heart tell you what is right.
Toward that end I submit the following video. As far as debunking the "ancient alien" theorists this is one of the best I have seen.
Believe it or don't believe it. It's up to you.
https://www.youtube.com/watch?v=j9w-i5oZqaQ
It is a bit over three hours long ... but easily divisible into several viewings. Have fun!