You are on the right track to go with a hub motor. There are 2 types, geared and direct drive. I have installed two hub motors with internal gearing in recumbent bikes, 2 wheelers. Both bikes are older recumbents, about 20 years old.
There is also less wear and tear on your drivetrain, because the motor power does not run through your chain and cassette, it goes from the motor/wheel directly to the pavement.
My first install was trouble free. My second install was ok, but I had a problem with the motor pulling the axle out of the frame drop outs, after 30 miles of riding. The axle did not seat deep enough in the drop out slots to get a good enough grip with the locknuts clamping the wheel to the frame. I had a welder us a die grinder to deepen the slots a few mm to get a better fit. I also got some serrated washers to use to dig into the frame more when tightening the axle nuts.
I still have to test it out in the spring to see if it is fixed.
You do have to fiddle with the axle to get it to fit in the dropouts, as it it is a larger diameter than the stock axle. The axle is round, but has two flat surfaces machined on opposite sides of the axle so it will fit into standard droupouts. And there are special washers that fit against the flat surface to keep the axle from turning in the dropouts and rounding them out. There is also a small torque arm to mount that helps keep the axle from turning.
The ebikekit.com web site has an online video of their manual and various how to videos for their products.
Suggest you view their online info. They explain their kits very well online.
I use their kit, and they have excellent customer service.