https://www.mangago.me/read-manga/hwang_young_s_misery/ similar to a tree without roots well in my opinion
https://www.mangago.me/read-manga/the_world_without_you/
https://www.mangago.me/read-manga/into_the_blue_water/
https://www.mangago.me/read-manga/vivarium/
https://www.mangago.me/read-manga/dear_teddy_bear/
https://www.mangago.me/read-manga/mary_jane/
https://www.mangago.me/read-manga/love_history_caused_by_willful_negligence/
Seriously, probably not Shounen Ai but if it’s similar to Lost in the Cloud or A Tree Without Roots, it’s fine