The 190mm rear/ 135mm front does not exist in off-the-shelf frames or complete bikes.
If you are committed to the rear 20x4" motor-wheel, I suggest finding a used ebike, working or not, with that size rear wheel. It will probably have a perfectly good 20" wheel on the front.
This 20"x4" wheel size isn't a standard in pedal-bicycles so you won't find anything that fits your chosen rear wheel other than an ebike. If you really need to run a 135mm front hub you will be shopping for a different fork to mount on any frame that has 190mm rear dropouts.