For me any Catalyst above 11.9 has made NWN behave erratically, though I've read there's some setting that can be applied in the CCC ('surface optimization' or something like that) in 12 and above for the NWN application to make it work properly.
However Catalysts under 12.3 don't fully support all 7000 series GPUs I think.
The resolution unavailability issue may be because you installed drivers that are too old and don't entirely work with your card.
Reinstalling newer drivers and experimenting with application settings for NWN in the CCC may help some but you may also be stuck between a rock and a hard place. Nvidia had a similar issue for a good while with its newer GTX series and drivers for NWN as well, unfortunately supporting games that are a decade old tends not to be a priority in driver/gpu manufacturing.