DO NOT UPGRADE MAC for CS6

How many years have you had CS6? At the very least, it would be almost 5 years or up to 9 since it was first released. Your "purchase" (which, by the way is not in any way ownership of anything, it's a license) prorated over that time is between $90-160 a year, or about $7.50 to $13 for every month you've had it. I'd say you got a pretty good deal for your "livelyhood and work"; it has paid for itself many many many times over.

The hardware has moved on, it's time to do the same.

"They are literally robbing me of an $800 purchase"

There was lots of software, across the board,  incompatible with Big Sur - basically any 32 bit software or software with 32 bit components (including installers).

Adobe have not changed CS6 or done anything to disable it. This was an Apple change.

The only way to guarantee to run any old software is to freeze the hardware and operating system along with it. Change either of those and you run the risk of the old software not running. The converse equally applies - trying to run brand new software on old hardware and operating systems can result in many frustrating issues.

Dave

It's best to check compatibility before you do a system update. If you have Time Machine installed, you can use that to roll back to the macOS you were using before. Photoshop has been subscription only since 2013, so Customer Care cannot give you a new version. The Photograpy plan (annual) is payable at $9.99 per month if you change your mind.

https://www.adobe.com/creativecloud/plans.html

~ Jane

This is old, old, news. Apple broke it deliberately. Adobe are delighted, of course, to sell Creative Cloud to people who must have the latest Apple stuff and don't do any research.  Adobe don't want you to pay for CS6 again, it wouldn't work. Instead, you are paying for the MASSIVE amount of work they have to do to keep up with Apple's games. It's all part of the Joy Of Mac!