Yeah, the unformatted capacities of 3.5” floppy disks were:

SS-DD - 512KB

DS-DD - 1MB

HD - 2MB

ED - 4MB

LS (floptical) - 21MB

Technically you could format some of the lower density media in the high density drives and get the expanded capacity (although you may have needed to modify the media a little - holepunch to make an HD drive see a DS-DD disc as “HD”), although it wasn’t always very reliable and depended on the physical media and the capabilities of the individual drives.

Different file systems used the 2*80 tracks differently, hence the different formatted capacity, DOS usually had the lowest, Macintosh in the middle, Amiga had the most (although the Amiga HD floppies were a bit of a cludge - the drive spun at half speed due to a limitation of the Amiga floppy controller, which was also the reason you couldn’t just use a “PC” HD floppy in an Amiga without modification).