During past mass-revocation events, Let's Encrypt has temporarily adjusted or removed rate limits.
For example, during the TLS-ALPN revocations in January 2022, the New Orders per 3 hours was raised to 1000 orders per 3 hours:
Large integrators (who are most likely to be affected by rate limits during revocation events) were advised to contact Let's Encrypt.
If you regularly - outside of mass-revocation events - exceed the rate limits, the subscriber needs to apply for a rate limit override form anyway. This is how it's been handled before ARI and I personally don't see that changing with ARI.