I have done this retrofit 2ish years ago and the parts I remember needing are:
New boot lock
2 struts
strut brackets as powered tailgate ones are stronger
finger trap sensors for the tailgate
Tailgate trim with hole for close button
close button
control module
loom
coding
Teile sind soweit vorhanden geht darum wo welches Kabel lang läuft und Position vom heckklappensteuergerät und es Tips zum durchziehen der kabel durch die gummitullen an der Klappe gibt weil sieht so aus das das die Stecker da nicht durch passen ( Kabelbaum ist Zukaufteil kein orginal)
I'll check something as I have a spare strut in my home garage.
Just to note, I didn't do this on my own car, I did this for a customer but 1 of the struts arrived faulty and the supplier didn't want it back... I suspect they knew it was faulty even though it was brand new!
Parts are available as far as it is concerned, it is a question of where each cable runs and the position of the tailgate control unit and there are tips for pulling the cable through the rubber grommets on the tailgate because it looks as if the plugs do not fit through there (cable harness is a purchased part, not an original).