FSR2 (not SSR2, that’s a typo) should work on any graphics card, your 6800 XT included; the statement just means they worked with AMD engineers specifically for optimizations on Ryzen/Radeon 7000 hardware.

Going with only FSR2 means Bethesda only had to optimize and bugfix their implementation of one type of upscaling technology, saving dev time. Consoles use AMD hardware, so they’d have to do that work with FSR2 even if they included DLSS, which means DLSS would be extra work for a marginal improvement over FSR2 for the subset of PC users using Nvidia.