I can't help with the race-rep paint scheme thing but it might be worth trying
e-bike insurance, to see if they're any better than the ones you've tried.
The renewal quote with my previous insurers (Master Quote, formerly Mitchell & Partners) for my 996
on it's own was £651.05 Fully Comp.
I just insured the Duc,
plus my supermoto
and also put my other half on the insurance too. Total cost: £648.50 Fully Comp!!!!!! The nearest I could get from anyone else for all that was £829 (and that didn't include a named rider)!!
Stupid not to really.