Ooph. The load, the winds, the hills, that pushes to the crank-drive, or something like a Mac 12t. That is a high-torque, low-speed motor. Rule of thumb is to maintain at least 50% of unloaded speed (which is neither really unloaded nor is it top speed, but everybody uses it) while hill-climbing to avoid overheating.

Crank-drives beat this problem by downshifting, at the cost of a few drawbacks mentioned earlier.

Give you a name of a solid, reputable vendor with a long history in the industry and a sterling reputation. Paul, at Em3EV. Website is a bit funky, he is based in China but a native Englishman. Virtually all these kits come from China.

I would message Paul what you have, and the info from your last two posts, include the health situation, and ask for a recommendation for hub, or crank-drive, and battery. He has some of the best batteries in the industry, also reliable, multi-level chargers for longer life.

Another is Justin Le at ebikes.ca. He is a bit of a boutique vendor, but sells quality merchandise much of which is developed in-house. I would also request a recommendation from him.

Definitely install the throttle. There will likely be times when pedaling is just not a recommended option.

Both of those websites contain a wealth of valuable information on things you haven't even thought of yet.