Does the "Server Backup Function" create one save per platform?.

[Vahlnir]

There is only 1 copy on the server at a time, but you can download it to any platform.

To expand on this, you can also download them as many times as you like. When I was messing with my PS5 settings to find a good middle ground my UI kept getting messed up, so what I would do was change my settings, log out and then download my settings again. Tedious, but effective.