Use RAID1 and choose stronger checksum XXHASH64

root@lotr:~# mkfs.btrfs -d raid1 -L btrfs_lotr --checksum xxhash /dev/sda /dev/sdb

fstab like so

UUID=<the_uuid> /btrfs_root btrfs defaults,noatime 0       0

Installed btrfsmaintenance package and edited /etc/default/btrfsmaintenance since we are not mounted at /

BTRFS_BALANCE_MOUNTPOINTS="/btrfs_root"
BTRFS_SCRUB_MOUNTPOINTS="/btrfs_root"
BTRFS_TRIM_MOUNTPOINTS="/btrfs_root"

Enabled these timers

systemctl enable btrfs-balance.timer
systemctl enable btrfs-scrub.timer

And refreshed the configuration (unsure if it is needed or a reboot does the same)

systemctl restart btrfsmaintenance-refresh.service