Hey OP, are you possibly having the same issue as this guy?
AMD R9 5900X
ASUS ROG Crosshair VIII Dark Hero
G. Skill (4x16) 64 GB DDR-4000 (can’t get it stable over 2,666 mhz)
Gigabyte Eagle Radeon RX 6700 XT
980 Samsung 1 TB M.2
2 34" Samsung 4k Smart TVs
Getting 90 FPS in Valdrakken, and upwards of 350 FPS in rest of the Dragon Isles and I have all my settings set at 10. Not noticed any difference if I set render scale to 100% or 200% except my video card fans actually starting to turn on when scaled up to 3840 x 2034 (200%). Would prefer to have UI windows to stop closing so I can look at auction house and crafting windows at same time other than having to lower my UI scale more than 89%.