ICANN can (theoretically) not force anyone to deregister your domain. If your stack is all outside the US, and everyone collectively decided to disobey the US, the Internet's decentralization would be true.

The hard part about building a decentralized network is finding out where to hide the centralization.

For the Internet, the centralization is hidden in the IP block and DNS Zone delegation. After this is done, that region is decentralized. A/I's problem was that the registry for .org is a subsidiary of IANA. With EU servers, EU DNS and a EU domain, EU clients cannot be prevented from connecting solely from the outside. The US would need a collaborator.