alex@Froutalie:~$ sudo -i
root@Froutalie:~# btrfs subvolume create /media/alex/Home/Home/
ERROR: target path already exists: /media/alex/Home/Home/
root@Froutalie:~# btrfs subvolume create /dev/sde1
ERROR: target path already exists: /dev/sde1
root@Froutalie:~# btrfs subvolume create /dev/sde1
ERROR: target path already exists: /dev/sde1
root@Froutalie:~# btrfs subvolume list /dev/sde1
ERROR: not a btrfs filesystem: /dev/sde1
ERROR: can't access '/dev/sde1'
root@Froutalie:~# btrfs subvolume list /media/alex/Home 
root@Froutalie:~# btrfs subvolume list /media/alex/
ID 256 gen 3876 top level 5 path @
ID 257 gen 3876 top level 5 path @home
ID 269 gen 3109 top level 5 path timeshift-btrfs/snapshots/2021-11-10_13-00-01/@
ID 272 gen 3796 top level 5 path timeshift-btrfs/snapshots/2021-11-11_13-00-01/@
root@Froutalie:~# btrfs subvolume create /media/alex/Home
ERROR: target path already exists: /media/alex/Home
root@Froutalie:~# btrfs subvolume create /media/alex/Home/@home
Create subvolume '/media/alex/Home/@home'
root@Froutalie:~# cp -rp /home/* /media/alex/Home/@home/
root@Froutalie:~# sudo vim /etc/fstab
root@Froutalie:~# btrfs subvolume list /
ID 256 gen 3911 top level 5 path @
ID 257 gen 3915 top level 5 path @home
ID 269 gen 3109 top level 5 path timeshift-btrfs/snapshots/2021-11-10_13-00-01/@
ID 272 gen 3796 top level 5 path timeshift-btrfs/snapshots/2021-11-11_13-00-01/@
root@Froutalie:~# btrfs subvolume list /media/alex/Home 
ID 257 gen 12 top level 5 path @home
root@Froutalie:~#