One major trick in distributed systems is to always attempt things in the same order. And then locally, you just store what you’ve seen, for “a long time”. That takes care of a lot of transactional issues — idempotency, retries, exactly-once delivery with no distributed locks, etc.

But as someone who builds distributed systems, I can tell you that transactions should be local. Anytime you want to lock something across the network (eg Canisters in ICP) so you can read it, that’s probably a code smell. You probably want to have evented reactive things ripple out, you do need idempotency, but you shouldn’t design your system to read remote state if you can help it. Only subscribe to remote messages.