> Insert is a destructive operation by design. In fact, writing any collection literal (e.g. {} or (1, 2)) is internally implemented by writing a deletion tombstone followed by the new values.

These range tombstones are also evil. If you keep doing it to the same partition, even at a rather low QPS, you can easily bring down some nodes by keeping their CPU at 100%. Only tested this with Cassandra though, not Scylla.