Hello,
There seems to be some non-compatible configuration with Pro SDK and ArcGIS Pro version.
We have:
ArcGIS Pro 3.1 (which we cannot upgrade)
VS Community 2022 and
While installing ArcGIS Pro SDK for .NET extension the only version available is for 3.4.
Any help would be appreciated!!
Have you taken a look at the requirement page for ArcGIS Pro 3.1 SDK? Make sure you have the correct .NET runtime version and the correct .vsix components.