I'm not as bad off as you. Was bed ridden most of the day but my e-trike give me some freedom. I need a reclined seat to spend any time on a bike/trike.
I do not know of any low quality trikes, not saying they don't exist. First do you want to purchased a trike that is power assisted from the company or get a trike and put a kit or DIY.
Trikes cost more than most bikes and fewer are made and only part of them are e-trikes. Good news there are more everyday.
Some trikes are more fragile than others, nothing to do with cost or quality. Weight and speed, road and off road. They come in carbon fiber, aluminum, chromemoly steel and titanium. Most are a mixture of the two.
The best e-trike will be the one that fits your needs. How much weight the trike needs to carry, can you do direct steering or need Under seat steering. Not saying one is better than the other. How do you plan to use it. Is it flat or hilly. Cost is a big factor but would not judge the trike on cost. What are your laws and do you plan to follow them or have something more flexible.