They can not stop Bitcoin.
Except it seems that they can. Make 51% of the hashrate comply with their OFAC sanctions as F2Pool have done, and bitcoin is firmly under their control. At that point they can censor any transaction they choose.
An exception to this is ThorChain which utilizes liquidity pools of coins on different blockchains to perform swaps. The fees are paid to the liquidity providers rather than a company.
Bisq is completely peer to peer in the same way that bitcoin is - you run the software locally and connect directly to other peers (over Tor). You can also run your own Robosats instance, and Robosats is developing processes to make it easier for these instances to talk to each other:
https://github.com/RoboSats/robosats/blob/main/federation.md