I used to use MiiVerse but I didn't really know if I'll lose any pictures that I would need because the charger port on my 3DS is broken, always dead. i haven't visited since like 2014 or 2015.
Plus Nintendo gave people the option to request an archive of their own downloadable post history
Yeah I heard there will be tools, but on the end message it says it may not be available for a while. They completely shut down miiverses' servers already.