Both Valkey and Redis have added new features that provide an atomic CAS.

SET key value IFEQ other-value

They also both now have a "delete if equal to value" functionality as well

# Redis
DELEX key IFEQ value
# Valkey
DELIFEQ key value

This might mean we can improve the efficiency of our session locks. Assuming we can, we could either optimistically try to use the new functionality and then fall back to legacy behavior or add an INI setting to opt-in to the new commands.