Large USB device format
Not sure who needs to see this but I know I spent a while searching and only got half the answer.
I wanted to use a large USB storage device with my MK4S, more than 32GB.
I had a Samsung T5 external SSD storage drive, 500GB, and wanted to use this and likely never remove it (until I upgrade the printer)
Found that using FAT32 Formatter (GUI version) partially worked but couldn't use the drive in the printer.
After some trial and error, I found that using FAT32, and allocation unit size of 4096 bytes yielded success!
Smaller overall storage of 449GB, but it works perfectly fine to print directly over the network from PrusaSlicer.
So there you go, give it a shot.
(Note: Limitations of FAT32 still exist; file size 4GB and overall storage size 8TB)
Let me know if you have success with other devices!