Thank you for your time.
Don't you encounter frame-drops;
1)When you pan the camera?
2)When you get the action camera view?
3)When you completely max out when by holding down the middle mouse button?
4)When there are too many soft particles from fires or enemies?
So far no frame drops throughout the 95 hours I've put in. Even during heavy effects like explosions and zooming in and out. Are you playing the base game or WOTC? I play WOTC and I've read that the base XCOM 2 is badly optimized compared to WOTC. They apparently did significant rework for the expansion to make the game run noticeably better, so maybe that could be the cause for the slowdowns you're facing?
If not, based on the four things you listed above, it sounds like a GPU bottleneck that would cause those drops. However your 5700XT should be more than capable of running the game maxed. Have you checked to see if it's a driver issue, some sort of AMD issue, or maybe even a heat issue where dust or something can be causing the card to overheat and throttle itself?
I am running the WOTC expansion.
PC is as clean as possible, no dust concentrations on the hardware.
Considering how many people still have performance issues, it might be a complex of hardware/software related issues, hard to nail, since the game was not optimized form the beginning for diverse configurations.
It's impossible that there is an objective bottleneck. Metro Exodus -60fps (foliage shadows turned off), Witcher 3 -60fps, Middle Earth Series -60fps, Sniper Elite 4 -60fps. And all of those games have open world environments with a huge draw distance. Can't justify a top-down strategy game running this crappy, unless it is using only one CPU core.