Why is space consumed differently in different types of file systems (ext, btrfs, ntfs)?

Question

Hard disks

Hello.
I recently noticed that if you format a disk partition in ext4 (or ext2 / ext3), then some place will be occupied by default.
But if you format the same partition in ntfs or btrfs, then much less space is taken up.
What is this place? How did I understand this under metadata?
If so, will this hidden space increase as the disk fills up? Or is it always static right after formatting?

Answer 1

ext4 by default reserves space (5%) available only for root. Adjusted with keys
tune2fs -m N /dev/disk
mkfs.ext4 -m N ...