I have over 100 RC elec planes in my garage. There are 20 of these with motors of 7 kw or more. From experience and maths, I can tell you within seconds how long any battery will last.
My paramotor is 26 hp or 19.5 kw. Level flight is at more than half power, but I am big, so let's call it 10 kw.
The best LiPo batteries can store 260 watt hours per kg ie. they will run at 260 watts for 1 hour and weigh 1 kg.
So 1 kw for an hour would need 4 kg of batteries. And my 10 kw motor would need a 40 kg battery.
This is why you find elec flight times of half an hour, because they limit them to 20 kg of battery!!!!!
So until battery technology makes another leap, elec paramotors will be heavy and of limited flight time.