Should I know something like critical strike damage or some term to make it godly as hell? I stack that only?

Brah the game is so dumb, so it is not that hard to figure it out yourself. Just get crit damage, overpower damage, skill that can overpower (preferably hota) and everything damage related (some of these are multiplicative).

Then, just grind the game, no matter where. Due to drop nature you will soon get better items, because drops are not random. That will lead to maximum perfomance of your character. The end.

11 topics on one page. A little research on your own can get you answers quicker than posting multiple topics/questions here within a couple of days waiting for hand holding.

Google is your friend.
Maxroll is your friend.
Icy Veins is your friend.