Books about an isolated/lonely MC with a dark backstory who’s mistrustful of others but finds family/connection?

Bonus if the MC resists connection despite being lonely.

I just watched the first couple episodes of Anne with an E. I really like it so far—super wholesome—but I would’ve liked it even more if, instead of Anne, it was a kid who also had a tragic past but completely avoids people because of it. Other than that, all the stars line up perfectly and it would be exactly the kinda story I’m looking for.

I’d prefer something less fantastical or sugar-coated. I’m okay with there being some disturbing elements.

I have no genre preferences.

Thanks to anyone that can help!