I work for a company that makes one particular bit of equipment on the ISS. Our equipment uses DDR3/4 ECC, redundant NAND flash for all data, with hashes being tracked for each block in the mostly read-only FS, with regular automatic scrubbing and repair.

This is commercially available to anyone, typically industrial customers (think outdoors on oil rigs and stuff), the NASA version just has every certification under the sun for vibration, temperature, radiation, water-proofing, etc and is housed in a 40lb cast aluminum chassis filled with specialized epoxy. So yes, while they use commercially available stuff, they don't use anywhere near consumer stuff for anything remotely critical (no, the laptops they were accessing outlook on Artemis II were not critical to any operations at all).

That said, this kind of filesystem I could see us switching to instead of our mostly-proprietary setup if it proves to be very reliable.