Hi Zuki, there may be some sort of comparison list available. Really sounds like you need to get your hands on one.

This is as far as i got

No fill tabs
No EC5 connection
Less styles
Less sounds <1GB rom vs 5.1 GB rom
Less user sample memmory
Lower quallity keybed
Lower build quallity (housing)
No drawbars/sliders
Lower quallity D/A converters.
No MAXX audio mastering effects
Less DSP (2 inserts for songs and 2 master effect)

looks like a quite extensive list..
Most of these things i use frequently on my PA4x..

I sent you a Private Message Zuki.

Donny...I think John has the big “G” in his future. My guess is the 4X will be finding a new home✈️