one of the misskey forks. imo "vanilla" misskey is lacking a fair bit of essential stuff (post editing being a giant one)
the most interesting ones to watch for now are iceshrimp (misskey v12 hardfork based on an early version of firefish, mainly focused on backend tech work compared to new features) and sharkey (misskey ”v13” softfork, aimed at qol changes and other feature work while keeping up to date with misskey itself)
akkoma is alright if you need something light on resources but I personally can't get used to it's interface
and mastodon is just... too bland in comparison to both