I'd like to switch my database from Snappy to Zstd compression.

Currently, it doesn't seem that it is possible to change the compression of an existing collection.

It would be nice if there were a way to do this, even if (for example) it required making a new replica set member which "re-compresses" the data to the new algorithm while cloning it.

As per SERVER-67726, the only way to do this today is to create a new collection and manually copy with mongodump/mongorestore. This doesn't seem to be a viable option, for uptime / data consistency reasons.