Look into Naono Bohra. She's got a ton of tankoubon and oneshots along those lines. One of my favorites is the Confession oneshot.
tbh I love older uke/seme mangas so here’s some I remember off the top of my head:
Saezuru Tori wa Habatakanai
Midnight Rain (CTK)
Yuuutsu na Asa
Castle Mango
Hana wa Saku ka
Hakidame to Tsuru
Not Equal. It's incest (I don't like incest manga but this one was 9/10 and I would recommend it.)
they asked for old men, all your recs are just some years apart... and the characters look about the same age range unless they tell you otherwise.....
Does anyone have any good suggestions for an older man yaoi. And I mean kinda like on doorstep. I’m looking for an almost old man, literally an older guy, dating someone younger. Can be seme or uke.