It'd be useful to see the storage stack:

lsblk -o NAME,FSTYPE,SIZE,FSUSE%,MOUNTPOINT,UUID,MIN-IO,SCHED,DISC-GRAN,MODEL

It's fine to omit the UUID. Mainly I just want to see all the physical
devices, their partitions, and how everything is being assembled to
make up this Btrfs file system.

Also useful info

sudo btrfs filesystem usage -T /mntpoint


Chris Murphy