Idk what genres you would be interested in, so here are some mangas from my list (mostly fantasy) that matched the dad MC criteria.
Reincarnated Devil's Plan for Raising the Strongest Hero is a fantasy manga about a demon raising a hero.
My Daughter was an Unsold Slave Elf is a fantasy about a magician adopting an elf daughter.
The Angel in Ootani-san's House is a slice-of-life about a man adopting an angel.
A B-Grade Adventurer With a Bad Guy Face Becomes a Daddy to the Protagonist and His Childhood Friends is an isekai about an adventurer adopting a group of orphans.
Kachou, Kekkon Shimashou!! is a BL that has a single dad MC.
Silver Shoes is a BL about two dads raising a son.
Demon and Song is a fantasy about a demon caring for a child.
The Wizard and the Red Pilgrim is a fantasy manga with an abstract art style and world-building. The MC has more of an uncle energy, but still caring.
The Human-Hating Demon Lord Has No Mercy for Little Girls is a fantasy and has a strange title, but is about a demon lord adopting a human daughter.
If u are okay with it,
My Brother's Husband tackles LGBTQ themes, MC is a dad who is coming to terms with the fact of his dead brother being gay. Still has a lot of parenting in it.