geepeeaay wrote:
Agree. Some of the software and files have been backed up on a LaCie 6t external hard drive
That's good to know and will help when you transition to a replacement computer.
When it hits, it hits hard …
When a computer fails, it's not fun. But yours was a 10-year old device, long past its normal lifetime. My employer requires replenishment of computers every three years. I know computers can last much longer than that, I still have several "museum pieces" that are working, including a 2010 MacBook Air, a 2013 MacBook Air , a 2015 iMac, and a 2019 MacBook Pro 16" which runs fine on Tahoe 26.6.2 but is being replaced soon with an M5 or M6 model.
Apple makes backing up so easy it seems odd that some people still don't do it. All one needs to do is connect a fresh external drive and say "yes" when asked if it should be used for backup. Once that backup completes, it can be used to migrate to a new Mac (when the old one fails) virtually seamlessly.
I would not bother with any steps to try to repair or rescue your old Mac. It is not cost effective. Instead, I would invest available resources in a new Mac, or if cost is an issue there, look at refurbished ones from OWC or Apple only (other providers are not reliable, in my view). Be sure to budget for an external drive for backups.