> the Switch cartridges use NAND memory which means if you aren't popping them into a system to refresh the charge every once in a while, your physical cartridge might not last as long

You've been paying attention to the wrong sources for information about NAND flash. A new Switch cartridge will have many years of reliable data retention, even just sitting on a shelf. Data retention only starts to become a concern for SSDs that have used up most of their write endurance; a Switch cartridge is mostly treated as ROM and only written to once.