If the bike were just a bike, I'd chuck the helmet, but it has a battery and pedal-assist, so theoretically I could pedal fast and hard, run the motor, and get the bike up to 15-20 mph (so far, I haven't done that, because I can only pedal steady and a tad better than slowish.)
If I wear the helmet, there's a 99.9% chance that I will overheat. This has resulted in me passing out, though not while on the bike. I did manage to get inside the house and my butt to the floor before the lights went out.
I did buy the most vented and well made helmet I could find. Still, overheating.
Definitely a conundrum for me.