There is already pretty decent documentation on the Mastodon website for how to install and configure a server:
https://docs.joinmastodon.org/admin/prerequisites/.
If you'd like to see the NixOS way I used, I could probably make a separate blog post about that.
When I got started with Mastodon, I myself was trying to find resources on when or when not to run your own Mastodon server, but had a hard time of finding that, so I hoped the post at least could help answer that for other people, although my experience with running Mastodon obviously is limited for now.