I googled ".net touch interface". Look what popped up!
[touch interface](https://learn.microsoft.com/en-us/dotnet/desktop/wpf/advanced/walkthrough-creating-your-first-touch-application?view=netframeworkdesktop-4.8)
Edit: I must be tired or something. My Affinity works with my pen just fine. (with minimal testing) I can draw objects, move objects, resize objects, rotate objects. Select various icons from the interface.
Now the UI! That could use some work.
PS; your "link icon" doesn't work.