You gotta try this masterpiece
https://www.mangago.me/read-manga/paljae/
Haven't read serena but there's this good historical yuri slow burn (they're not together but it kinda feels like they are). Historical so you get some misogyny and sexism but the 2 girls support each other.
Newlywedded noblewoman's husband grows ill so she hires the beggar girl to teach her how to nurse her husband as the beggar girl's father is blind. The nursing thing is somewhat of a cover up so they can spend time together. There's some angst but it all works out in the end.
https://www.mangago.me/read-manga/her_shimcheong/
Slowburn reccs like serena?