Interested bystander, but no MB3 here. Just working from the MIDI Baby 3 Editor, so correct me if I’m wrong.
I see a count & send option for a Program Change. Start & Stop PC; Step; Count to configure. That should get you incremental presets on a switch action, scrolling upward. I don’t see negative number entries, so I’m not so sure about scrolling down.
Send Single Value (or Send Counter?) could bring you back to a starting point preset [PC #1 of 25, for example). I don’t see where that Editor currently supports programming more than one Main Footswitch, though.