I have an idea (that was already mentioned by superdude so I cant really take full credit)
Streetpass. IDs.
The first/next time a user opens the app, it asks them for an id, which they can make with any letters or numbers (besides ones that look...
I've updated to version 0.2.4, deactivated streetpass for super pokemon rumble (I didn't have it activated for pokemon rumble world when I initially posted either) and I'm still getting the same crash, it usually happens when I get to 3/X after...
I may try the new ram site, and download more RAM to my Switch. Not sure if ddr3 is the right ram
for it tho. Edit- no it uses floppy Ram, just like @AncientBoi