If you're looking for a heartwarming comedy manga about scary Yakuza guys doing cute things, may I suggest Way of the Househusband?

It's about a notoriously badass Yakuza that ditches the Yakuza life to become a househusband. Basically it has one joke (haha scary guys knitting menacingly) but it does it well from what I've read. It's a comfy read that will make you smile.

The one where he reunites with his old boss and makes his dog a sweater is a good one iirc.

He also gets into a fight with a Roomba.