Tool for creating btrfs snapshots
$ aur_helper -S btrfs-snapshot
# btrfs-snapshot --help
/etc/btrfs-snapshot/root.conf
#!/hint/bash
SUBVOL=/
DEST=/.snapshot/root
NKEEP=10
# systemctl enable --now btrfs-snapshot.timer
Or
# systemctl enable --now btrfs-snapshot@root.timer
OnCalendar is set to daily by default. Edit the corresponding systemd timer if necessary.