Unfortunately he's given you bad advice
You can use 128gb, that's a good size.
https://www.amazon.com/SanDisk-128GB-MicroSDXC-Memory-Adapter/dp/B08GYKNCCP
https://www.amazon.com/SanDisk-128GB-MicroSDXC-Memory-Adapter/dp/B08GYKNCCP
try removing id.dat from root of sdcard and then reboot.