You might have the answer to this now, but I've been looking into this myself (considering purchasing a Strive On), yes it would appear to be compatible:
https://www.canyon.com/en-gb/gear/bike-parts/spare-and-wear-parts/spare-wear-parts/bosch-powermore-250wh-range-extender/10014093.html
What price did you get it at? Currently at €4500, very tempted myself.
I tried to order the Kenevo Comp from IBK earlier in the week but the order wouldn't go through for some reason.
IBK prices and stock seems to fluctuate quite often from what I've noticed.
I tried to order an S4 Kenevo Comp on Wednesday but the order wouldn't go through.
The Experts were also available in all sizes/various colours.
Tried ringing them also but no answer...