Reading possible faulty RAID backup drives

I am using a 2014 MacMini with an Intel Core i7 processor and running Monterey 12.7 OS.

I am also running a La Cie 2 BIG NAS which was new in December 2014. It contains two 2Tb SATA drives.

The RAID is used for my Time Machine backup which has saved me more than once after hard drive failures. I am unable to access this now.

The RAID does not run constantly, only being switched on every few days to protect my data. Lately the process has been much slower than I recall but that may be due to the drives being near to full and having to clear space.

A few days ago when I tuned it on the front light  began to flash blue and red which I assumed was the system matching the 2 drives. However the flashing has continued  for up to 20 hours suggesting a problem.

Both rear lights are also flashing Red and Blue.

The NAS appears in the sidebar of a Finder window but when I click on the icon it says that connection failed.

La Cie’s own software, Network Assistant (now obsolete I believe) and La Cie RAID Manager cannot access the rdrive

Time Machine does not appear able to access any of the backup files.

I assumed I would be able to remove the two drives from the case, fit them into another hard drive enclosure and check to see if they are working. That way I could get an idea if it is the drives or the NAS that is at fault.

When I do so Finder tells me the drives are unreadable by the system. Disk utility can detect them but does not give any information about the contents. The Disk utility window is below.

What format is the drive likely to be formatted in. I believe there were HFS+ when I set it up but have read that modern OS use APFS.

Is it safe to run Disk First Aid on these two disks with my Time Machine backup on them.

Any advice anyone can give will be appreciated.