I read Solo Leveling and I'm interested in something similar:
-weak to strong mc (either gender is fine)
-no fanservice/ecchi
-leveling up (optional)
-preferably not isekai

If it's similar to the webtoon unordinary that would be cool too. I didn't like the gamer and have read most popular mainstream shonen

Skeleton Soldier Couldn't Protect the Dungeon

Maybe Room of Swords ( https://www.webtoons.com/en/sf/room-of-swords/ep-1/viewer?title_no=1261&episode_no=1 ). It could be classified as a weird Isekai though.

The Gamer is a good read

Nulla in mundo pax sincera
"Always go too far, because that's where you'll find the truth." - Albert Camus