Have only used a 256gb (is it really that much slower? I don’t think it’s bad at all)

This is the official Nintendo Micro SDXC. Just a Nintendo themed Sandisc meant for switch but I use it on my 3ds and it’s perfect.

https://www.amazon.com/SanDisk-MicroSDXC-Memory-Nintendo-Switch/dp/B07QD6R5L7/ref=asc_df_B07QD6R5L7/?tag=hyprod-20&linkCode=df0&hvadid=363067789809&hvpos=&hvnetw=g&hvrand=5943219165949655995&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1024543&hvtargid=pla-773890336970&psc=1&tag=&ref=&adgrpid=82977529144&hvpone=&hvptwo=&hvadid=363067789809&hvpos=&hvnetw=g&hvrand=5943219165949655995&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1024543&hvtargid=pla-773890336970

Btw you can shorten most URLs by deleting everything after the ?, since all that is just meaningless tags. For example: https://www.amazon.com/SanDisk-MicroSDXC-Memory-Nintendo-Switch/dp/B07QD6R5L7/ref=asc_df_B07QD6R5L7/