I totally understand that. With the Storage option in Recalbox set to AnyExternal, Recalbox was writing boot profiles to every device I plugged in. Since a fresh boot profile gets written, so do basic Kodi files, and every time I'd inadvertently load a boot profile from a drive I didn't intend to, loading either RecalBox or Kodi resulted in my entire rom/media libraries getting overwritten.
I fussed with that option so much trying to get it to work that I was scared of booting into RecalBox with my external hard drives plugged in at all; which means I never saw the option to set a static individual drive as a Storage option.