This topic always surprises me. I do not understand the sequence of logic that leads people to build synchronisation mechanisms based only on webhooks. Webhooks aren't at-least-once, nor at-most-once, nor are they guaranteed in-order. Some people build systems to make them more reliable, but if you really care about the data you need to think of a webhook delivery as best-effort, a bit like UDP. That's before you get…
Another benefit is that you get to exercise those disaster recovery mechanisms regularly as part of the normal functioning of the system, rather than a specialized path that is only rarely exercised (and thus may be broken when you need it the most).