I noticed recently that Garmin Express was taking up over 30gb of hard drive space on my computer and that this was predominately caused by Garmin retaining old downloads for the application and maps. I think it would be a reasonable thing to delete old map files once new ones had been updated.
For example: Map_Map.ActiveUS.2020.20 may mean that I don't need to keep Map_Map.ActiveUS.2019.10 anymore (or 2019.20 and 2020.10 too)