If you're thinking of trying Mastodon, I would recommend joining an interest-specific or locality-specific server rather than one of the general purpose servers, because the local community is likely to be stronger and more engaged. You can always jump ship later if you find it's not your thing
Some examples:
- https://fosstodon.org for FOSS - https://infosec.exchange for infosec - https://sfba.social for the bay area
There's a map of locality-specific instances here: https://umap.openstreetmap.fr/en/map/mastodon-near-me_828094