DLSS Swapper
This tool allows you to force change DLSS versions for some games.
Download DLSS Swapper: https://github.com/beeradmoore/dlss-swapper
Download DLSS version files: https://www.techpowerup.com/download/nvidia-dlss-dll/
LTT video demonstrating the app
Keep in mind one thing: it is a UWP app, it requires importing a certificate to allow installation.