How to gain aviation, aircraft, and sim knowledge?

That was going to be my recommendation. But you don’t have to read it all at once. Read a bit, practice in the sim, rinse and repeat. You’ll pick up a lot that way and you’re getting the info from a reputable source.

King Schools now has a YouTube channel with a lot of great material and they are the gold standard for ground school instruction. They’ve been around a long time.