Ozone asynchronous deletion performance optimization

Background:
We have a Cluster which will write many small key. The user will merge these small keys into one big key, so these small keys will not be stored for a long time. So we have almost the same QPS of delete requests as writes.
The current key deletion performance cannot meet the requirements, the disk is using less and less available capacity, but in fact, only a small portion of the user's valid data