Photoshop 6 was released 20 years ago, so there are of course no patches for Windows 10.
Since it worked before on Windows 10, you can try to run it in compatibility mode.
Using the File Explorer, go to C:\Program Files\Adobe\Photoshop, locate the file Photoshop.exe, right click it and choose Properties. In the Compatibility tab, try setting the compatibility mode to Windows 7 or Windows XP, and click OK.
Then double click the .exe file to launch Photoshop. It might work, and it might not.
PS6 (not to be confused with CS6 ) is a relic. Photoshop Elements 2020 is light weight, affordable (under $100), no subscription needed, a short learning curve and it's light years ahead of what you're using now. Best of all it's compatible with modern operating systems. Try before you buy!