Estonia used to be a good hub but since AMLD5 you'll be branded a criminal enterprise until you prove the government otherwise even if you have their "license". Furthermore most of the banks there will refuse to deal with you unless you got serious money to begin with. Tax wise it's pretty good compared to most other european nations, if your country has a double tax treaty with them it's even better. However i wouldn't go there unless i had serious cash to work with or else i'd get the clown treatment where ever i go. If you do have the cash, and plan to physically relocate, Estonia is definitely a good option, given the large pool of cheap developers, proximity with europe, access to EU banking, and decent taxation.
I would avoid
Seychelles and Mauritius unless you plan to set up shop there with a real office. Many crypto companies set up shop in the
Seychelles and then opened subsidiaries in their home countries to access banking but it's an expensive process, especially given the licensing involved.