Currently, when adding in data which is in a different datum to that of the map properties, ArcGIS Pro assigns a datum transformation based on the maximum spatial extent of ALL the layers and basemap listed under the Contents pane. If you have a Esri basemap then this spatial extent will be a global extent, which is seldom the scale at which I work (and I suspect the scale at which most of us work).
My idea is to either (1) drop the basemap from any transformation calculations, or (2) under Project>Options, provide the user with the option to exclude the basemap from any datum transformation calculations.
