I went from DAIN-APP to Flowframes, and then came back to RIFE-APP because the UI suited me, and the results met expectations and used 100% of an RTX 3090's resources. For whatever reason, Flowframes didn't seem to leverage all the hardware power I had at my disposal.
My workflow begins with Topaz Video Enhance AI (which also fails to use 100% of my hardware resources) to enhance frame size and clean up noise/color/banding/blocking/edge enhancement, then RIFE to interpolate framerate to something suitable for a modern high refresh rate display, then ye olde HandBrake to repackage the completed project in a more reasonable h.265 filesize