Hi!
Welcome to Microsoft Q&A forum.
Regarding your first question, The folders exists to hold OEM customizations (branding, drivers, preinstalled software, etc.). On a consumer PC(which is your PC) where you create the recovery media yourself, Windows doesn’t put anything there, because there are no OEM customizations to apply.
Second question, FAT32 is required for UEFI boot (most modern PCs use UEFI instead of Legacy BIOS) and FAT32 is used intentionally to ensure maximum boot compatibility.