Whether they are some kind of social misfits, or have some problematic behaviour that causes them to be ostracized by people around them. Ideally the plot revolves around them overcoming their own weaknesses together, each inspires growth for the other, be each other's strength, etc. But something less introspective, and focusing on how they're no longer lonely because they have each other, would be fine too. Please no BL or harem. Preferably slice of life. Thanks in advance 🙂

DONDAKEE!!

Try koe no katachi. Both the leads are kinda like misfits

Coulomb Fille perhaps

The outcast and his bride?

A bit late, but you should definitely check out yahari ore.