cassandra disk space not freeing up

I have Cassandra on K8s. It's being used as part of a temporal persistence store. I'm seeing that my disk space is ever growing. I'm deleting some completed workflows, but they still occupy disk space. I have set **gc_grace_period** to 6 hrs, and **LCS** is the compaction strategy being used. Forcing manual compaction will result in high disk I/O and CPU pressure, which can be problematic in my production environment. Is there any other way to solve this problem?