Why do you need to run in “ultra nightmare” when just dropping it to “ultra” would look pretty well identical when playing and run fine?
True enough one day 8gb won’t be enough, but picking some silly settings that don’t really add much just because you can isn’t the way to prove it.
Truth is games are built around the limitations of the cards, not the other way. So as most cards have 4-8gb of memory games will have settings that run well with that much memory. 8gb is only going to become a problem when most low-mid range cards in use (e.g. popular in steam survey) have more memory then that, which is not going to be for a long time.