Taking care of my little helpers.
If you have a spare flash drive, you could format it to FAT32/exFAT and see if both PS4 and PC read it.
Can PS3's see FAT32? Maybe that's why I never managed to get my PS3 to play media from an external drive. All my drives are formated in NTFS.
I don't have a PS3 anymore, but I can tell you that it definitely did read FAT32 formatted flash drives for media, not hard drives though (unless they changed that recently). The only console that accepts NTFS is Xbox One- for media, not as a system drive.