some of the fear/hand-wringing for non-professional social users is the FOMO of not being on the "cool" or "cache" mastodon instance. for *non-pro* users, it will not matter nearly as much which instance you are on, especially since you can bounce later. advice: try to join multiple to secure your handle, then see what happens and trim the one(s) you don't like.
notice i typed *non-pro*. the impact of the "wrong" instance is real for people with large followings or the need to pay rent with it
also the threat of racism/bigotry grows at least geometrically with your follower and melanin count, as well as any sort deviation from a saltine gender identification. mastodon may not last as any sort of place for non cishet nonwhite folk. it might, but likely won't without moderation across the fediverse to keep asshat ofay nazi bullshit at bay