Change the quota size for an APFS volume I created one APFS Container for the whole of my external hard drive.
I created several volumes in that - some with quotas.
I have now discovered that one quota is now too small. I used diskutil apfs list /dev/disk10 to show me the Capacity consumed and the Capacity Quota.
How do I change the quota for an APFS volume under BigSur?
Unfortunately, there is no way to change an APFS reserveSize nor QuotaSize without destroying the APFS volume and recreating it.  You can only set these values when adding the APFS volume.