"My School Life Pretending To Be a Worthless Person"
OP mc but everyone thinks he's really weak
https://www.mangago.me/read-manga/my_school_life_pretending_to_be_a_worthless_person/
"Reaper of the Drifting Moon"
MC has terrible childhood and want's revenge (I think? part 1 was great, the rest was mid)
https://www.mangago.me/read-manga/reaper_of_the_drifting_moon/
"Standard of Reincarnation"
MC weak, dies, reincarnates and gets strong.
https://www.mangago.me/read-manga/standard_of_reincarnation/
Doesn't really follow what ur asking for but one of my fav novels/mangas.
"Trash of the Counts Family" or "Lout of the Counts Family"
MC says he's weak, is actually quite strong but always gets hurt, and all the side characters r trying to protect him (very entertaining and great concept)
Hope this helped :33
i think maybe regressor instructional manual or i'm not that kind of talent
Any good novel or manga or basically anything with a funny misunderstanding like the mc is weak but everyone thinks they're strong or something like that and even if it's not not that kinda misunderstanding it's fine