Resolved on my end as follows:
- Uninstalled FSR from the first location I'd instaled it to (Program Files folder on system drive) and installed in its own folder on root directory of D: drive. (D:\FSRealistic)
- Then noticed that the original desktop shortcut still worked, and manually deleted the original install from the Program Files folder on the system drive - not sure why the uninstall did not remove it for me.
- Then because I am on Windows 11, I manually added it to the startup by pressing Windows+R keys, running "shell:startup", then selected the "New...Shortcut" option in the upper left and browsed to the FSR executable, then "Finish".
- This will make it show in the list when going to the Settings menu -> Apps -> Startup option, where you can then enable it to launch on startup.
On my old Windows 10 system that I just upgraded from, the launch on startup worked flawlessly by default ever since first installing the original FSR (non-Pro) release, so I will just chalk this up (in my case) to a Windows 11 UAC thing.