http://www.mangago.zone/read-manga/gragon_basement/
^it's very fluffy in the beginning but then it gets serious and a bit angsty
Fruit, Gateau au Chocolat by Kitahala Lyee
Koi ga Ochitara by Ueda Aki
Here U Are by Djun
Blue Sky Complex by Ichikawa Kei
Kiraide Isasete by Hijiki
Love Nest by Minaduki Yuu
Path to You by Sinran
Cherry Blossoms After Winter by Bamwoo
Kokoro Kanda Neko
Konomi ja Naka to by Mita Homuro (kind of)
I could keep going but but for now this is a pretty brief one. I am always looking for stories like these as well because I love the idea of developing a relationship before making them have sex, so if you want more at any time just hmu.
If you haven’t read it yet, try http://www.mangago.zone/read-manga/ten_count/ . They develop their relationship first before doing anything.
Update! I just read an AMAZING story that I hope you enjoy as well. The characters are super fluffy (despite the story not being much like that), and they develop feelings for each other before hopping into a sexual relationship (if you exclude some BJs). It's a bit kinky, with many references to light bondage and light BDSM, but it's such a soft story that I think even those who aren't into that kind of thing would enjoy it. I hope it resembles what you're looking for since, as someone who has been in an ongoing quest to find good BLs that develop relationships before sex, I can safely say this manga satisfied that need (for me at least). Happy reading!
http://www.mangago.zone/read-manga/yakuza_wo_shibatte_ii_desu_ka/
same! i've read this recently and it was like the perfect refresher. good pacing and development before everything else. http://www.mangago.zone/read-manga/kyou_mo_ashita_mo_asatte_mo/
Thank you to everyone who commented! I finally have something to do this quarantine (๑•ㅂ•)و✧
Anyone got any bl recommendations where the uke and seme develop their relationship before they do it? Or just a Shounen Ai that's fluffy but does have angst and a well written plot and characters? Sorry if it sounds like i'm asking for much it's because i've read too many shit mangas/manhuas/mawhuas lately.