I was recently trying to install shapely and geopandas onto my ArcGIS Pro base conda environment (which I now know is a bad idea), but in the process of installing/uninstalling packages, my Python version got upgraded to 3.7.10 and connections to several environments were broken. Now I can't open a project in Pro without an immediate crash, and I can't "conda install --revision 0" because that leads to a bunch of PackagesNotFoundErrors.
Ideally, I would like to get a clean new conda base environment, but failing that, I think my best bet would be to uninstall/reinstall Pro. However, I don't want to do that unless I can be sure I'll be able to do that with my single-use license.