My Fazua (Kinesis Rise) hasn’t had any issues over a couple of years of riding -I think the OP has been unlucky, sorry to hear about it.
I have two batteries for mine, as the spare is about the size and weight of a full water bottle – got mine from Halfords for about £350 I think.
You could buy a spare OP, get riding and then either sell the new one when it turns up (there’s a FB group for Fazua Riders) or use it as a range extender for the future? FB group is also a good place to keep an eye on any common faults, but I still have the impression that although Fazua isn’t faultless, failures seem much lower than the stories you hear about some other brands and constant replacements.