Hard drive not showing as Scratch Disk

Hi all,

I've read every post I can find about this problem and tried lots of solutions and so far nothing is working:

I am running on Windows 11 (fully updated) and Photoshop (I have reinstalled several times in the past 24 hours) which is the latest version (25.6.0). 

I have no disk space on my local disk on my laptop (C:) and I have tried using both a brand new SDD card and a brand new USB 3.0 external hard drive as additional space, but neither of these are showing up in the scratch disk options. I have tried formatting as both NFTS and exFAT and neither option has worked. 

I have so far tried:
- Running Photoshop as an administrator 
- Saving files to the locations (able to do this, but still not showing as a scratch disk option?)
- Given full access to Photoshop
- Made sure the disks are not read only

- Uninstalled and reinstalled

- Changed the settings to allow more disk space

- Run the extra storage as both NSFT and exFAT 

And several other things that I've found on the forums, but to no avail.

Any help very very very gratefully received!