Exponential back off with random jitter is the solution there. It can be a bit tricky though because the random jitter can reduce throughput if it’s too generous or not generous enough.

For instance backing off 53 ms is a lot of latency. Backing off 1 μs may still result in a collision, requiring two or three backoffs before it resolves, where a longer pause on the first backoff might have resulted in quicker recovery.

Optimistic locking is a statistical model just like bloom filters are, and scaling something 20 or 100 times higher is a hell of a lot of runway. Especially if the failure mode is a person sharing someone else’s account or using a laptop and tablet at exactly the same time.