I mainly read manga and I think there's some manga that I felt the story is good, but quite underrated.
1. Tamanokoshi Goyoui Shimashita ( https://www.mangago.me/read-manga/tamanokoshi_goyoui_shimashita/)
At first, the story is quite typical of hopeless person (gigolo/scammers/criminal) got picked up by a wealthy person. But, as the story progress, it doesn't end with them "happily ever after", but the mc is trying his best to pull his life together, by start working honest job and pursue his careers, also it shows ml's struggles and problems, which is very rare to see a story with plot like that.
2. Kowamote no Rinjin ga Ω datta Toki no Taishohou ( https://www.mangago.me/read-manga/kowamote_no_rinjin_ga_datta_toki_no_taishohou/)
This is an omegaverse story, that have quite unique plot. First, there's no typical of "alpha r*pe omega in heat, then becomes mate after", in fact, the alpha is able to control himself around the omega, when they're in heat. There's also some slightly differences of alpha and omega, like mostly omegaverse story is only about dom/sub in omegas & alphas, but this one, have different types than that. Well, it may have dub-con at the start, but trust me, it's really good as you read the story.
Both story is still ongoing tho #-.-)

What's an underrated BL more people should know about?