What do you mean exactly ?
Are you using unified kernel and trying to fix the entry in the firmware ?
Are you using the default grub loader ?
[root tip] [recovery] Basic Manjaro Linux Rescue and Recovery
This is likely where your luks container is stored
Below snippet look like an edit of a file not stored correct e.g. the m character as part of /dev/m409d90 .....it should probably have been this UUID or some form of
It should probably have been this UUID
And this is apparently your containers id
I am guessing your luks container is at /dev/sda2 so you can check with cryptsetup luksUUID /dev/sda2.
If the observation is correct the output should be 62409d90-a545-493b-8d67-cf28d7aca04b
If you are using a default installation of Manjaro - using the default installer - then you will have /etc/crypttab and you will have /etc/default/grub and any of these may contain the invalid reference /dev/m....
Exactly how you can fix it - I cannot say - because the extent of the damage is unknown.
And I have next to no knowledge of btrfs but perhaps the above observations can help your forward in the recovery process.
You should probably try using btrfs tools to investigate the health of the internal file system.