Mairimashita! Iruma-kun
robin my love <3 Ahem. Sorry. Got something stuck in my throat there. On a more serious note, the best way I can describe 'Mairimashita! Iruma-kun' is 'Poor MC gets caught up in something bigger than him, but he improves and achieves friendship in doing so.' The manga follows a similar structure to the classic action trope of growing in levels, but it also has a focus on the rest of the cast. While it is less so than Iruma himself (he is the title character, after all) I can say with certainty that this manga has made me fall in love with each and every misfit in Iruma's class, as well as every other character Iruma encounters. It's just a feel-good manga for people looking to feel good.
Kakegurui Futago
While I've read a few chapters of Kakegurui - Compulsive Gambler, I can say with certainty that Twin has given me a much more enjoyable reading experience. Twin follows Mary (or Meari, if you prefer) when she first starts attending Hyakkaou. Like Yumeko, she makes a strong entrance by beating the class bully. Unlike Yumeko, however, Mary feels like she's actually trying to strategize and win. In general, Mary was much more likable as a main character, and following her journey through Hyakkaou was beyond riveting. If you wanted Kakegurui but less horny, I believe Twin has got you covered. Also, Hoshizuka is for sure gay for Mary.
Kumo desu ga, nani ka?