If you have to get a ew van, be aware that the conversion can be almost as much as the van itself!
Depending on what kind of conversion is done, this can be very true.
I've gone through the process a couple of times (when my wife who had MS was still alive) The first time was with a Bruno lift device that was able to lift an electric scooter into the back of the van. When Marg was no longer able to get into the van on her own, we then got a motorized seat that swung out and down which allowed an easy transfer from scooter to car seat. Those 2 devices were the lowest cost one could get at the time. We looked at having an electric ramp installed with the floor lowered to accomodate the scooter....the cost? ...prohibitive!!
Believe it would be a good idea to visit one of the companies in your area that specializes in this. Do a lot of research first before you make any decisions. And the advice of finding a used van was good....trying to find one will be another matter.