I have the read out from the lsblk, blkid, mount and cat /etc/fstab in the attached file.

# btrfs subvolume create /home/1tb
ERROR: target path already exists: /home/1tb

# btrfs subv list /home/1tb
#lsblk_and_blkid.txt# blank return
# btrfs subv list /
ERROR: not a btrfs filesystem: /
ERROR: can't access '/'