I disagree re not getting anaerobic fitness on ebike.
Look on the body as a machine, a complicated one, but never the less a machine.
Mine is currently capable of producing around 140 watts(guess)... I can use that 140 Watts to jog, cycle, swim or whatever I want... pretty much indefinitely... Trouble is that 140 watt when running, cycling is hardly enough to get up hills, so I make it give 160 going up and on a bike almost nothing going down.
Now our bodies train much better at steady state out puts... Going into short term debt, coughing and spluttering actually is of hardly any benefit at all. Benefits to heart, lungs and muscles are achieved with sustained and probably minor rates over our max steady state out put..
On an ebike you can use your 140 watt out put combined with that of bike to avoid serious short term oxygen debt but sustain a beneficial output for a time long enough to achieve real gains. Going into short term oxygen debt will simply tell the machine... Stop. (especially so when weakened by illness)
It might feel to be beneficial to pant, cough and splutter, and it might help you think you are training but you aren't.
Get on your ebike, set an achievable constant out put, use the econtroller accordingly, ie more help on hills, less so elsewhere and cycle for at least one hour. (a heart rate monitor helps, ie train to a certain constant heart rate..., when not in AF I train to 140)
Jogging when unfit and going into short. term severe O2 debt with soaring heart rate is extremely dangerous and actually is of very little if any benefit.
All this from my heart surgeon..
Train to a raised but sustainable level and enjoy it. Ebike perfect tool.