Rob, Your understanding of Segwit activation is incorrect. All miners have activated at this point and do not need any further implementation. The implementation task now has shifted from the miners to the wallets and applications. Very few of the applications have turned it on. BitGo, of course, was one of the first to implement.
The increase from 1MB to 2MB will not prevent you from running a node or not afford one. There is no evidence that this would bear a problem.
Finally, Segwit2x does nothing to hurt or improve Bitcoin’s decentralization properties. I also would encourage you to find a single supporter for Segwit2x that wants to see it centralized. It’s just not true.