Yeah, S3 is frankly a disaster. People use it like a filesystem and if you have billions of objects, it very quickly becomes a nightmare to manage. Size of data is a complete non-issue, it's all about the number of objects.
Sure you can destructively destroy the drives. But you could also just use KMS on the S3 bucket object and then toss the key and close the buckets. Gonezo.
Dropping a btrfs subvolume or snapshot is pretty fast. ditto for zfs.
Any system these days should allow near-instantaneous admin operations for just about any reasonable request. Subtree move, delete, or rename should all be instant. Similarly, any simple ACL changes should be instant.
Similarly, data movement should scale linearly with the volume of data, not the number of objects.
Object storage is best for larger files with bulk updates. Either write new files entirely (best for S3) or append/replace where supported (like Azure/GCP). Any further structure and metadata should be maintained at a higher level with pointers to the raw files in the object store.
There are products like Stablebit Cloud Drive [1], ObjectiveFS [2], and other storage companies that handle all this for you. You can also look UtahFS [3] to see open-source code on building something yourself.
1) https://stablebit.com/CloudDrive 2) https://objectivefs.com/ 3) https://blog.cloudflare.com/utahfs/