I think the EC5 pedal is near extinction

No current Korg arrangers facilitate the EC5.
I have no confidence that this will be "replaced" on the PA5x - Korg believes that it was "not used much" and can be "replaced by a MIDI pedal" - so NOT true!!!!
Maybe if Korg ever provide the MIDI Implementation details for the PAnx series, then there is a little bit of hope for a MIDI solution.
Several EC5 functions are NOT possible using a MIDI pedal - like VAR-UP, VAR-DOWN and a whole heap more....
There are still a few EC5s available so, if you use an EC5 and you're thinking of keeping that PA4x,3x,2x,1x,pa800,i2/i3,i30 then it might be worth grabbing a spare pedal before they totally disappear....
Cheers
Pete

https://www.korg.com/au/products/accessories/ec_5/