I have both a misskey and lemmy instance. For both I used https://servarica.com/ with the cheapest summer deal Flying Fish SSD. It's like 55 a year. (Or you can pay monthly but I'd highly suggest to save up and pay yearly) (kinda lie, I got a bigger one for lemmy but it's overkill)
If you have never installed software before on a VPS (virtual private server) you're in for a learning ride. If this is the case, be patient, don't give up.
Misskey is similar to mastadon. You can also look into calkey which is similar to misskey.
The hardest part of setting it up was the settings. But since I already know Docker and whatever it was easy going otherwise.
Though I still don't have email working... Bleh
Misskey you add relays. Relays are like lists of instances to join in the fediverse. You then block instances you don't like.
Lemmy, you block instances you don't approve and can set it up so you can white list as well.
Also important, lemmy doesn't automatically add other instances. How it works is, any user on your instances has to subscribe to another using the full search key [email protected] then once ONE user is subscribed, everyone else can search it via keyword.
Because of that I created a bot that went through all my approved instances and subscribed to all communities in there. It stopped around 3500 subscribed communities. I'll have to run it again sometime.