I can't see anything out of the ordinary in the Task Manager screenshot. This is how it should look.
The system info also looks fine - except you are really low on disk space. 85 GB isn't much. I'm unsure whether this could be your problem - for Photoshop it would be if you have a lot of big files open, and a high number of history states. Reducing history states to 5-10 will dramatically shrink the scratch disk requirement.
However, ACR runs outside Photoshop's address space. It will normally not use the scratch disk, nor will it use memory from Photoshop's allocation, it needs its own. It all runs independently from Photoshop, and if RAM or VRAM runs out, it will go to the system pagefile. If that disk space is already taken by the scratch disk, it could slow things down.
All of which boils down to making sure there is enough disk space. When it runs low, it affects different processes at the same time, possibly competing for the space left. I'd say number one priority is to clean out your system drive.
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