me too!
I don't know if these are your style but u asked favs so one of the first I read was "at the end of the road" I really like it. It doesn't have that many spicy scenes if I remember right. I also like "payback" but it's not finished so I'm waiting for more chapters.
Though I don't think these are what you would call old gems
AT THE END OF THE ROAD RAAA
This isn't old at all though?? It's actually pretty recent even?
When the Killer Falls in Love! The plot is really different from 19 days, but I think they're similar in how they mix comedy + serious moments.
Its really difficult to find old gems like these now adays guys pls recommend me ur fav mangas