Gregory's ServerAnother thing that could be noted is that many of those projects, even on the Top4 list, aren’t mutually exclusive, but the other way around: it is VERY likely that one user can have an account on all 4 of those services, as they fulfil completely different needs.
Personally I have 5 different Fediverse accounts that all can be seen as my daily drivers (out of my 11 accounts in total) depending on what I wish to do, and it is very difficult to swap one out for the other as they are focused on different things.