I'm very fond of Yan(kee)dere Kanojo (
both versions). Here's a few other, slightly out-of-view romance series I think are worth giving a shot:
Uwagaki - Fairly lighthearted romcom by the author of Immortal Hounds (speaking of which, does Immortal Hounds count as a weaponized romcom too?)
My Brother the Shut-in - Man struggles to stop being a shut-in and change himself, largely from the PoV of his teenage sister. Has a shoujo look and style, but is otherwise a rather grounded story with two parallel romances.
Also, the author may or may not be a slight, real life brocon themselves, but it's pretty sweet.
Sumomomo Momomo and
Midori no Hibi - Part of the "used to be relatively well-known and had anime adaptations, but are now completely forgotten" 2000s romcom club. Both hold up pretty well and are a lot of fun, and I won't rest until people finally admit that Sumomomo was always the superior Shinobu Ohtaka manga.
Any genre is accepted here, as long as it includes romance and is not widely popular.
CRIMSONS - "Top 10 shonen manga sex scenes."