I never said anything about uninstalling DS4...
I asked if you used such a software because you need one. As far as I know, the EPIC game store being the terrible platform that it is, still does not have any kind of controller support built in. Furthermore, Sony released official support for the Dualsense controllers on PC but not for the Dualshock controllers if I recall correctly. In other other words, you need DS4 for your controller to be recognized by your PC.
Download and run DS4 again. Leave Steam closed completely, be certain it's not running in the background. Then try again. If you had both Steam and DS4 running, it's entirely possible that Steam was interfering with DS4's processes. It's happened to me a number of times, it happened when I switched to DSX to use my Dualsense Edge too. You need to be certain there is only one form of controller support running at any given time.
If that doesn't work... then you might try adding the game as a non-Steam game in your Steam account and use Steam's built-in controller support while closing DS4 to avoid conflict.