Ive got the same issue, but 9800x3d and 9070xt..
What i found after putting diagnostics on my screen was the GPU for some reason just gradually lost power over time. For EG it’d start at like 350 - 370 watts, then gradually just drop to like 280, then 250, then 220, then 180 etc.
What immediately snaps it out of it is if mid mission I go escape → options → video. That’s it, just close the menu after that. My GPU immediately goes back up to 350 - 370 watts and normal performance.
No idea why, it’s literally only darktide this happens on, no other game.