I think it’s worth to check out https://github.com/superseriousbusiness/gotosocial
It’s far from „done“ and has a lot of rough edges, but it’s easy to setup and probably good enough for a single instance!
It's a single binary that can use SQLite - from what I've heard of the Mastodon source, that's like a trowel compared to their intergalactic planet crusher that occasionally crushes parts of itself. Pleroma would be more of one of those big circular strip miners - a reasonably heavy faff and a half (don't let your OS upgrade Elixir! Pleroma might not restart!).