Out of curiosity, I just checked, and while the CS6 installer is 32-bit, Photoshop CS6, at least, is 64-bit.
The .app icon shows the "circle slash" overlay, however, and attempting to launch it from the Finder (Sequoia 15.1 running on an Intel Mac) yields the OS-level "needs to be updated" alert without actually exec'ing the binary.
The Mach-O executable in "Contents/MacOS" loads and runs successfully when called directly from a shell prompt, however, and displays an application-generated "Some of the application components are missing…Please reinstall…" alert.
Which is actually encouraging, given that I'm attempting to run it directly from the Master Collection .dmg image without actually installing anything, which, given all the prerequisite detritus Adobe apps habitually scatter around the system when installed, I wouldn't expect to work even on a supported OS.
Less encouraging is the fact that the app-generated alert box text is blurry, suggesting the application wouldn't properly support Retina displays even if it could be cajoled into running.