I don’t know why this worked but I deleted the modules folder it had Rhino 3dm in it, then after deleting I was able to check the check for your plugin and it worked. I think uninstalling the older plugin didn’t work for me and it left this older module folder? A new module folder was created but nothing is in it. I was able to import a rhino file and 3dm is on the import file list.
With Blender 4.5.3, I still have the message “No module named Rhino3dm”. I checked in the subfolder “extensions\user_default\import_3dm”, i can’t see any Rhino3dm python package.