This is not just a NAS issue. I got a brand new iMac last year and spent 3 months in utter **** because of this issue. The first day I had the issue where time machine wouldn't back up to a dedicated external disk. I called. I went through months of troubleshooting-- if that was the only issue, I could make due until they fix it by manually backing up my data as I do anyways, however, my applications would randomly quit. It got to the point that I couldn't edit for more then 5 minutes (I'm a professional photographer) without the computer freezing and then shutting down and restarting. It was beyond insane. All while having no time machine backup to rely on anymore because it corrupted my disk and I was never able to make another backup despite my probably 50 calls to apple and my own trouble shooting. I had to beg and plead and cry to be able to have a replacement and keep the other computer for a week while I manually moved everything from disk to disk to ensure all of the hidden files and things were there. It was ****... This is my career. This isn't something I use send email and watch Netflix.
Fast forward 8 months-- and here I am again. Computer started acting a little funny again. Time machine is now not working and I don't know if my current backup is corrupt. My computer has 128gb of ram, but it is running super slow. I went through so much trouble shooting and nothing worked last year, they kept saying the issue is on my end, but clearly this is an OS issue. I went onto my sister's 9 year old Mac last year and was able to run the same programs (albeit incredibly slowly bc it's such an old computer) and the drives worked fine except my messed up time machine drive. I'm back to square one and am extremely stressed that Mac still has no answers and I can't do my job and likely have lost my time machine backup. And I can't go to Catalina on a new computer--- I asked them last year how I could revert because I was pretty sure it was related to Monterey or an internal issue. Either way, I am totally screwed here and can't believe this is happening again and Apple has no answers. I have used western digital drives for over 15 years with no issues, always have a dedicated one just for time machine.
If anyone has figured out anything- please let me know. I am desperate. We all need to be filling out the feedback because this is definitely an ongoing issue. I can't just go buy another $4500 setup and run into the same issue.