Affinity V3 is a Microsoft Sandbox type of program, so it is impossible to find the Affinity executable with normal means. However there is a quite simple solution for this problem.
Clear your desktop screen (makes the work easier).
Start Affinity.
Open the Task Manager (ctrl-alt-del).
Look for the Affinity executable.
Right-click on this entry, and choose Open File Location.
A window will open, and at the top you will find the complete directory specification (Local Disk (C:) > Program Files > etc.)
Keep this window open.
Start PhotoLab or PureRaw.
I’m using PureRaw at the moment, so the next few bullets are for PureRaw. However, PhotoLab has similar settings.
Add an image to the lightbox.
Click on Process with Preview.
On the bottom of the right sidebar you will find the Open in Application setting.
Click on Select Software.
A window to Program Files will now open.
Do not attempt to find the Affinity executable with your mouse, that will fail.
Instead, type the full directory + file specification from the Task Manager Window in the File Name box, so “C:\Program Files\WindowsApps\…. \ Affinity.exe“
Click on Open.
If everything went ok, then you will see the Affinity application in the Open Application setting.
Now when you process an image, it will directly appear in Affinity.
That will be OK until the next version of Affinity is released, which will have a completely new path to the executable, requiring you to go through this routine again.
That is true, which is why the previous posts in the topic are helpful.
However Affinity by Canva and the previous version, Affinity Photo, are available as ‘normal’ MSI/EXE installers. Both my installation of Affinity by Canva and Affinity Phot are of this type.
That means I don’t have the problem that this topic addresses. It also means other users can avoid these problems by ensuring they install the MSI/EXE version of Affinity.