This genre is probably too common a theme in mangas/animes, and so many people look for this sort of thing, but actually what I'm looking for here is a lot different.

What I DONT want is fricking harem mangas with a perverted loser with a bunch of abusive and annoying tsunderes. Been there, done that, enough is enough. I also don't want anything that is like 'in this manga, so-and-so is always OP!' I want it to be the MAIN CHARACTER, nothing with the side character as what I'm looking for. Also, I don't mind shounen, but unless the mc gets strong fast then I get really bored quickly, because it just becomes your typical battle manga (ie: the first half of Naruto). Also, no sports genres -_-

What I want is either:

A manga with an mc that is literally too overpowered to care about life. (I LOVE one punch man and saiki kusuo no sainan). Please no airheaded op characters tho lol. Also, I've tried to read Mob Psycho 100 before, but I just couldn't get over the art style T-T a bit too much for me in the end.
I've read:
-Ore to Kawazu
-Pretty much all the 'reincarnated in a fantasy RPG world' mangas you can find out there

OR:
A manga with a hella awesome mc that is either never loses his cool, (ex: Origin by Boichi, great manga btw) or even a revenge-type plot (such as Berserk, MY GOD I LOVE THIS ONE).
I've read (can't remember them all right now, but I've read probably twicel the amount of mangas you could find on the shelves of Chapters):
-Gantz
-Monster
-Berserk
-Vagabond (found this one boring, sorry)
-Gintama (I hated this one tbh.)
-Ubel Blatt
-Dear Boy
-+ much, much more.

Thanks, I'd really really appreciate some new recommendations![b]

You could check out the category Protagonist Strong from the Start.

Actual recs:
Akame ga Kill! (if you take the protagonist to be Akame, not Tatsumi)
Claymore (kind of)
Epic of Gilgamesh
Gosu
Helck (everyone is OP in this one--I am not kidding)
Immortal Hounds
Koutetsu Kishi Chevalion
Maoyuu Maou Yuusha - "Kono Watashi no Mono Tonare, Yuusha yo" "Kotowaru!"
Rain
Tsuyokute New Saga
Vinland Saga (though from what you seem interested in, you might not like the second half of this one as much)
Wizardly Tower

Also, if you're new to MU, I would suggest starting some lists (if you haven't already), so it's easier for folks to rec stuff you haven't read before.

Ah I am new as far as being registered here, but this site is by far my favourite for finding manga 🙂 thanks for the recommendations! Three of those I haven't read before, and a few I've tried reading but never got into, though I've seen them recommended quite a bit before, so it might be worth it if I try again.