Bottom line:
If you want best possible quality in your videos and don't have any issues with limited VRAM or long rendering times, deactivating DLSS makes sense.
However if you're doing e.g. 4k or even higher resolution videos and you risk running out of VRAM and rendering times become a bottleneck in your process DLSS usually doesn't degrade quality notably even compared to the native resolution FSR2 temporal anti-aliasing we have today.