I think I've solved my long loading times and shader issue in Path of Exile.

I'm using two SSDs:
Slower one (C:) has Windows
Faster one (D:) has POE and caches

First, I moved the game cache by adding this under [GENERAL] in production_Config.ini:
cache_directory=D:\cache

But NVIDIA cache(Bigger file size than poe cache) was still writing to the slow C: drive at C:\Users\YourUsername\AppData\Local\NVIDIA.

So I did this:

Created D:\NVIDIA folder on the fast drive

Booted into Safe Mode

Deleted the NVIDIA folder from C:\Users\YourUsername\AppData\Local\ (or you can move it to D: first instead of deleting. I suggest deleting it.)

While still in Safe Mode, opened Command Prompt as Administrator and ran:

mklink /J "C:\Users\YourUsername\AppData\Local\NVIDIA" "D:\NVIDIA"

Restarted normally

Important: Replace "YourUsername" with your actual Windows username.

Loading times got way shorter after this. Might not work for everyone but worth trying.