I don't begrudge anyone who has a working copy of old software on an old system. (Adobe CS6 people, this one's for you.)
That said, if you upgrade that system and your software breaks, that's on you. You knew the software was listed as compatible only with older operating systems, but upgraded to Windows 11 anyway? That's neither Microsoft nor Adobe's fault.
Software isn't designed to run on any version of an OS in perpetuity. It's optimized for whatever most people were running at the time it was shipped, which in something like CS6's case, was ten years ago. That was the Windows 8.1 / Mac OS X 10.8 Mountain Lion era.
That's also why banks and airlines and the Social Security Administration still run really ancient code, because they're immensely complex systems and they don't have the luxury of throwing away decades' worth of software development by hundreds of programmers, or risking the system going down and vital services going offline.
Old software has dependencies on services / code libraries provided by the OS, that if they go missing or change, will break. Newer operating systems often change out the 'plumbing,' so to speak, to correct flaws, or to provide foundations for new services, etc.
Analog TV is no longer broadcast, electrical safety standards improve, we don't put lead in gasoline or paint anymore. All of these were done for good reasons, but they cause an annoyance to people with old TVs, house wiring, or cars whose engines will now start knocking. Such is the way of the world.
There are some solutions:
Virtual systems. If your computer is fast enough, you can emulate an older computer and install an older OS / software in a so-called 'virtual environment'. Parallels, VMWare and other solutions exist and there are open-source and free solutions too. This helps with the problem of hardware eventually going bad and dying, too.
Just keep that computer on the old system, and if you need a new system (for instance, to meet company security policies, etc.) get a separate computer for that. If it's for work, let your company or organization provide it and keep it separate from your creativity station.
Use a backup system that lets you roll back to previous saved versions of your computer setup. Apple's Time Machine does this on macOS, there's Backup and Restore in Windows 10 / 11, but for older systems, you may need to create and export a restorable system image snapshot of the current state of your system, and if your upgrade breaks things, use that snapshot to wipe and re-install your old system.