I self host a calckey instance (what firefish was called before a week ago and I’m too busy to update atm) and it integrates just fine with everything else in the fediverse. The cool thing about the fediverse is that user numbers don’t matter because it all ties in together.
I spun up a Calckey instance a week or so ago. It’s leaps and bounds better than Mastodon.
You gotta federate. Try adding some relays to your instance and follow hashtags of things you enjoy so when your people post you can interact with them. As someone who self hosts their own calckey instance (similar to mastodon) the early stages basically require you to interact with peeps.
I have a small and humble set up. Pihole on my old Pi3, OpenMediaVault, Kavita, Qbittorrent on my Pi 4 and my other Pi 4 is running fucked up Lemmy and Mastodon instances because I’m new to this stuff.
Invidious exists. While it is still youtube it at the very least respects your privacy.