Sorry we cannot reproduce your problem, the project with your data works so well in my machine.
We hadn't noticed the slow when pan&zoom, and without any exception found in output window.
I found in fact you hadn't upgraded all packages to the latest, so I just remove all the packages and reinstall them again.
Please try the sample which I tested and see whether it have different result in your machine, you don't need to modify anything just wait it restore the packages from NuGet.
8948.zip (199.4 KB)
If the sample still be so slow, that's should be an environment issue.