Like what? Oh and copyright is free by the way your stuff is copyright protected as soon as its tangible
It’s $35 dollars int he US, and company Trademark $275 and $325,but you have to make sure it’s not already owned. If you still feel interested do your research and read into some online documentations about it. (Here: How to Trademark a Company Name - WSJ)
I’m not sure if you are 18 or older, but there’s really no point in trying to do all this until you have a game ready in post production, or just closer to release so it’s not a waste of money. Also as for what games you should consider changing into doing are small arcades, puzzles, and so on that you can play on mobile. Do yourself a favor if you don’t have a team or team experience and make a game that isn’t going to require 10-12 modelers alone for a vast 3D world because if you wanted quality on top of quantity you won’t get it without paying someone.
It’s honestly up you to figure out something to try, I recommend making some sort of warfare mobile app game, probably in 2D and if you are learning to program study AI. https://www.gameacademy.com/how-to-make-an-indie-game-part-i-the-beginning/ You should also check out some Indie articles to learn when to kill or keep an idea and what works and what doesn’t.
Copyright is not a Trademark, in any case that’s not really important
I’d be interested in helping you out