Not exactly what you're looking for since as far as I can tell this only allows to enable/disable one emuMMC partition, but I wouldn't be surprised if the option to switch between different partitions is added in the future since several people will likely request it.
https://gbatemp.net/threads/emummcconfig-atmosphere-emummc-configuration-tool.541137/
(And don't bother feeding the troll, you're wasting energy and I'm pretty sure he enjoys it.)