Same FPS in 1080 as 1440, struggle to maintain a consistent fps

Title says it all really. Ive tried so much to finish this game but i cant get it to perform for the life of me, ive wasted god knows how many days just trying to get it to run well. I get around 80FPs on average (capped to 80 to try and stabilise the fluctuation of my fps) at 1440p in the countryside but as soon as theres an object to other than trees in frame i can be getting between 38-50. i know this isnt unheard of, but it happens in even the remotest of locations. And heres the kicker, what makes this all the more baffling to me is my GPU utilisation is very rarely (if ever) above 80%, and my VRAM, CPU and RAM usage is also fairly low while i know my CPU isnt the best in the world, it gives me no issue usually and the usage is so low i cant see this being the main issue here (no more than 70% on my CPU at the very very rarest of times). i also have noticed that i get roughly the same performance in 1440 as i do when i lower my res to 1080, not sure what thats about, hopefully someone here can help me actually manage to finish this game, as even a consisten 55fps would be better than having huge peaks and troughs, as the stuttering from the frame jumps is super difficult for me to cope with, ideally id like my draw distances to be high as possible as pop in is something i hate haha, thanks in advance.

Specs:
2600x (watercooled so no thermal throttling)
5700xt Red Devil (no OC, temps well below 90C)
16GB 3200mhz RAM
SSD 500GB

Solutions attempted:
Driver wipe and fresh install
Settings at low medium and high all trialed individually (HD texture pack seems to either increase my FPS or reduce it negligibly, huh?)
Vsync Off
reseated GPU
Upped my fan curve to be more aggressive (again no real difference)
Optimized performance mod (no help really)
usual settings are the high preset draw distance sliders, high/v.high texture, low particles, physics, post processing and volumetrics, all other settings at medium. Again i have tried every combination of settings with minimal frame consistency if any change at all.