Note: (Creating this ticket as a placeholder now. Need to updateticket description and come up with solid plan to address this issue).
Currently, TTL deletes struggle to keep up with TTL inserts. Despite improvements from PM-2227, the issue persists. To address this, we should consider implementing a backpressure mechanism to throttle TTL inserts when necessary, and (or) explore the possibility of a multi-threaded TTL monitor (that can benefit Serverless)

This came out of SERVER-82863.