These exist and cost about £5
Secondly bluetooth is a universal standard and any Bluetooth headphones should work wit an iPhone, I use Sony ones with mine.
All the Deliveroo guys have those ones, as do the phone snatchers in London, which have a throttle rather than a regular e-bike which just assists your pedalling.
An electric bike is all the fun parts of cycling without the hard work. Definitely recommended. The suggestion for Decathlon above is good, they’re well trusted and very competitively priced.