$2000 a month? Not sure what kind of workload you’re thinking of. You can run an instance with several thousand users with pretty minimal hardware.
Decentralization is a matter of structure. There is no central “federation” that you speak of that can blacklist you. Getting defederated from an instance isn’t a collective descision, it’s up to the individual server owners to decide.
And the odds that you work hard to build a server up and then find yourself defenderated by all major instances is incredibly small. Normally indicates that the server is actually a pretty toxic.