Hi,
I tried to have application specific settings on my pen tablet driver, but then I encountered the same problem.
Let me post here because this one is the latest with this topic.
Put simply, these paths below worked for my case.
I assume the path needs to be updated manually every update though, mine is 2.0.4 MSIX fyi.
"C:\Program Files\WindowsApps\SerifEuropeLtd.AffinityDesigner2_2.0.4.1701_x64__3cqzy0nppv2rt\App\Designer.exe"
"C:\Program Files\WindowsApps\SerifEuropeLtd.AffinityPhoto2_2.0.4.1701_x64__3cqzy0nppv2rt\App\Photo.exe"
"C:\Program Files\WindowsApps\SerifEuropeLtd.AffinityPublisher2_2.0.4.1701_x64__3cqzy0nppv2rt\App\Publisher.exe"
You can get the path this way.
Run Affinity Designer 2
Task Manager > Processes > Unfold Affinity Designer 2 (2) > Right click Affinity Designer 2 > Open file location
Hope this helps!