It totally depends your budget, and the vast majority of the cheaper bikes while cheaper are unfortunately quite heavy. A 23kg = 50lbs in old money. 23kg is actually good for an ebike, many of the cheaper models are weighing in at 27kg or even near 30kg. 30kg is 66lbs thats incredibly heavy.
Another thing is they're limited in sizes, trying to accommodate riders from 5'5" to 6'5" and there are specifications in the size, top tube reach, frame size, leg length that arent really proportional for someone your height.
Next is the level of spec, and unfortunately the cheaper the bike the lesser the quality of the parts that make the bike go, and stop, and its mostly these parts that fail sometimes in under a year, meaning the maintenance is expensive and that I fear puts people off.
My suggestion, would be a lightweight road Ebike. The battery is considerably smaller and therefore lighter, and while that affects the range, i suspect with your condition you are not looking to ride from John O'Groats to Land's End, rather just happy to get out and about on shorter journey's, some fresh air and light exercise.
So I would think something like a Ribble(A well known and respected road bike manufacturer) and their Ribble Endurance SL It comes in 5 frame sizes.Starting at XS, whereas the cheaper ebike come in usually 3 or sometimes 1 size only.
This is probably one of the most important aspects of getting the right fit. Teh smaller frame is built in proportion for the smaller person, the reach is less, the leg length is less, its not trying to fit everyone, just the size of the person the frame size is suitable for.
Many of the bikes you can see look like 1/2 a mile from saddle to bars. Do you have extraordinary long arms ?, i guess not. So it is best not to buy something thats trying to suit someone with your reach, as well as some strapping gent with hugely long arms. Many of these 'one size fits all' look like they were designed around something like an orangutan.
The level of componentry is of fair to good quality, and certainly of good enough quality not to suffer from premature failure.
It is based around a carbon fiber frame, carbon fiber forks, Shimano 105 groupset(thats the bits like the gear shifters, 2x11 speed derailleurs, including shimano 105 hydraulic brakes,Mavic Ksyrium S Disc wheelset, (I know you said you knew nothing about bikes, but I list these spec's so you can at least research them for yourself)
It is not very very cheap, but at £2999 its not bad for a bike of this weight and with quality components.
The bike weighs 12kg or 27lbs, which is less than half the weight of many of the cheaper bikes.
Whats more it doesnt automatically strike you as actually being an ebike, so its a good looking thing.
It even comes in a range of colours
Link to model -
The ultimate stealth e-road bike with discreet hub- driven power assistance and market-leading weight.
www.ribblecycles.co.uk
