Korg’s original plan was for USB peripherals to replace the hardwired multi-switch option. Iirc, this was supposed to work on PA4X as well, but seemed to have got shoved to the back burner in the light of the 5’s many, many other issues.

The good side of going USB would be you weren’t limited to just 5 switches, and a host of options are available with a variety of switches. But it would still be able to access the full range of choices, many of which don’t necessarily have MIDI codes (so you can’t use MIDI foot controllers for full functionality).

You can also opt to use USB pad matrix devices if you prefer to operate the functions with your hands.

But given Korg’s monumental list of features to either fix or add back wholesale, it’s possible to understand why it’s taking so long. In the meanwhile, check to see if the functions you particularly want have a MIDI code to operate, and a MIDI foot controller like the Behringer could work…