Need to Access RAID1 HDD via mdadm

[gcok]

long story short

problem
I can no longer access TNAS (stuck on initialzation)

The device needs its drives reformatted from BTRFS to EXT4

relucatntly tried remote support but it did not happen....

I have am now trying to fix myself by accessing RAID drive on a spare pc using linux

tried

mdadm -D /dev/md125
lists RAID info

attempting to mount

I get mount:unknown filesystem type 'LVM2_manager

has anybody successfully gained access to their TNAS drives via mdadm

as I side note I do have a windows machine if its possible to and/or easier to use that if its possible at all ?

objective

I need to gain access to the files on either of the RAID drives so they can be backed up to 3rd drive and TNAS can be setup again