If you need "transactions" with microservices the traditional answer is sagas - eg multiple transaction boundaries that dont fully commit until their entire set of things is complete by passing a message or event to the next system, and having the ability to rollback each thing in a positive manner, either by appending new correct state again or "not ever adding" the original state.

The problem with sagas is that they only guarantee eventual consistency, which is not always acceptable.

There is also 2 phase commit, which is not without downsides either.

All in all, I think the author made a wrong point that exact-once-processing is somehow easier to solve than exact-once-delivery, while in fact it’s exactly same problem just shaped differently. IDs here are secondary.