Adrenalin May 2022 (22.5.2) now available

Try turning on in-game FPS counter, it will show GPU utilization. If in benchmark mode your GPU utilization sits above 95-97% then game will eventually freeze during actual gameplay. So lowering graphics settings or resolution to reduce GPU stress is the way to fix it. According to my testing using environmental textures and geometry below Ultra provides best GPU utilization drop.

Also be sure to lock your FPS, edit resolution to 16:9 (reduced number of pixels GPU has to push significantly), and lower display refresh rate if your display panel supports it (2019 MBP do, 2020 iMac I don't know). I personally add 48 or 50 Hz display refresh rate using CRU, enable GPU scaling using AMD control panel and edit scaled resolutions list using SRE (CRU and SRE are both by ToastyX at his forum) to include 16:9 resolutions (i.e. by default you have just 2560x1600 but you can add 2560x1440 and will have slim black bars on top and on bottom of screen). I also feel FH5 runs better in 16:9 for some reason. Be sure to try using 18:9 aspect ratio since it's more gains and FH5 adjusts to ratios very well (Elden Ring doesn't do 18:9). Editing scaled display resolutions can be done on any computer.

To get 48 & 50 Hz settings for your iMac's display panel (if you don't have this data) you an use macOS app SwitchResX or ask somebody (maybe here or there) to extract and provide the values (here's an example of what values you'll need, example macOS screenshot in that thread is from SwitchResX).

After adding refresh rates and/or scaled resolutions don't forget to:
- restart driver using restart64.exe provided only with CRU;
- switch your display refresh rate in Windows advanced display properties;
- turn on V-Sync in FH5 and lock it to 48 or 50 fps;
- set your Windows energy saving power plan maximum CPU usage to 99% to prevent CPU throttling and excessive heat (I also keep minimum as 1%). It's quite lengthy to explain but essentially it's easy and fast to do.

Same techniques can be applied to FH4 and it's a bit less demanding but doesn't look as good as FH5.

P.S. As a last resort you can try running FH5 in Windowed mode and use IntegerScaler to get a pixel-perfect 2x scaling. This will improve performance tremendously but the picture will look pixelated as on 1920x1080 screen.
P.P.S. To cap fps below 60 in Elden Ring you need to use RTSS or third-party app Elden Ring FPS Unlocker from GitHub (AMD driver's settings don't work).