Changed to 105 cassette and derailleur

So finally my Prime works perfectly. Just to point out that I’m mainly riding on tarmac and maybe grass occasionally in London UK.
I have a new ebike mechanic to help out and he’s amazing! As I’m not going to be off-road, he suggested an 11 speed 105 cassette ( better quality steel and much smaller low-gear cogs). This means I no longer require the derailleur hanger extender. I’ve also now purchased the 105 derailleur which will be fitted today. Which all means a much more compact gear configuration more suited to road riding and very nice transitioning right across the cassette…It was slipping before.
Only change was to remove one cog from the 105 cassette as it appears that the free hub is for 10 speed and not 11…no biggy - again for street riding.
We also managed to swap the gear cable for a better quality one and the cable sleeve - which from the factory, was in two sections…not a great idea??
I have looked at all of this as the drive train is going to be badly punished with a motor at this high level of torque and output…
I also did not fit the throttle as it will add to the destruction of parts and is in fact, illegal here…..I don’t think the bike is though!!!😉😇🤟