something with the same vibes as : she is also cute today nan hao & shang feng tamen de gushi 19 days bromance 18 unlimited salt friend ... anyway , you got it
try - Otaku's Offspring (it's in webcomics, a slice of life highschool rom-com about the son of a fujoshi and the daughter of a weeb.) - Toorigakari ni one point advice shiteiku type no yankee (not entirely school life but it's still a slice of life rom-com) - Bitchy Mean Girls (it's literally what the title says.) - Horimiya (added it here too coz why not?) - Aishiteruze Baby (it's highschool comedy about a guy being entrusted to take care of his niece.) - Sasaki to Miyano (hehe y'all already know why.) - Chuubyou Gekihatsu Boys (just thought that it was funny when I first watched the anime, so I also added it here.) - Handa-kun (u probably already know this one.) - Have Your Heard? I'm Sakamoto (u probably already read this too.) - Chen Mo's Survival Guide - Yaoi Gods in The Skies (not entirely school life but still related to it, a fantasy slice of life rom-com about gods trying to matchmake couples as they decend in the human world.) that's all I can think of so far, I'll add stuff if I remember some since everything in this list is something I've either picked up now or read just a few years ago before pandemic that I already forgot some of it.
After School Lessons for Unripe Apples. It's on Webtoon; it's a funny, bright, romance with really interesting art but it's not complete.
Daily Lives of High School Boys Nichijou The Disastrous Life of Saiki K Great Teacher Onizuka Kill Me Baby!!! Hinamatsuri Himouto! Umaru-chan Lucky Star Pop Team Epic
If you don't mind 0 rom school & slice of life, then maybe: Dragon Ruri (just recently translated, so not much ch yet) Flying Witch Breakwater Club Diary Yuru Camp
who's Mr president-comedy and mystery is amazing-ongoing swimming lessons for a mermaid-completed yeonwoos innocence- shy cute guy x handsome* cool girl he can't be this dumb! they're pretty lighthearted with comedy, romance, HS life...idk any mangas on your list but I enjoyed these manhwas a lot!
Ouran Host Club (+) Lovely Complex (+) Salad Days (Shinobu Inokuma, (+), mostly one shot stories w/ multiple couples) Karekano (+) Gekkan Shoujo, Nozaki-kun Tomo-chan wa Onnanoko ((+), anime ver planned for next year) Hitomi-chan is Shy With Stranger Shiota-sensei to Amai-chan (translator MIA) Koi wa Ameagari no You ni (+) K-ON (+) Yankee-kun to Megane-chan (+) (+) -> complete/finished