Is it possible to limit the size of an APFS volume? My understanding is that with APFS, volumes exist inside containers, and the volumes all grow as much as needed, as long as there is space in the container.
But I want to limit the space for the volumes. I have a 2TB disk with two volumes - one for Time Machine and one for general storage. I don't want the Time Machine volume to take the entire physical disk. Sadly, there is no way (in macOS 11 Big Sur) to delete Time Machine snapshots, so I need to limit its space by limiting the size of the volume.
When creating an APFS volume, you can set a quota. In Disk Utility, in the sheet to create a new volume, choose Size Options and set a Quota Size.

The optional quota size limits how much storage this volume can allocate.

This can't be added or changed for an existing volume.