One thing you can do is use :ets.slot/2 to do random probing of the cache and evict entries. The way to do so is simple, just have a process every few milliseconds check a random set of keys (say, 50 keys), and check if they expire. If >25% of keys were about to expire, repeat this process again instantly, until the % of keys expired in the batch is <25%, then poll periodically.

This is how Redis versions prior to 6.0 implemented key expiry. It's a very simple algorithm and can prove quite efficient at evicting expired keys without having to constantly scan the entire range.