Similar enough to some of your beliefs, there’s a theory called the multiverse theory(or something along those lines - I’m pretty bad at recalling names); basically, all forms of media, whether it be books, video games, etc. even our very own thoughts and fantasies, all exist in their own worlds. Now here’s where it starts to vary: some people say it exists because we thought of it, ie. “I think therefore I am.” Some say that those worlds have always existed and that there are no original thoughts - that somehow, someway, an author or designer was ‘sent’ the idea of that certain world, and proceeded to make a book or show about it. And some say a whole lot of other stuff; the multiverse theory is pretty flexible, and people add or subtract parts of it depending on their experiences.
Also, have any of you read “The Egg” by Andy Weir? It’s a short story in which time is relative and we’re actually all one being. You, me, 16th century Chinese peasant girl, French noble, your neighbor, etc. We’re all one. “We” live out lives over and over in an attempt to achieve godhood, and ascend. Eventually, after all lives possible have been lived, we attain permanent godhood as one being. Pretty interesting stuff and adds a whole lot of meaning to the word “brother.”
As for my personal beliefs, all I know is that I don’t know anything. I’ll get back to you in about 20 years’ time. Still pretty confused.