They’d be better off buying wagons and mules.
I’ve thought that if any outfit would benefit from EVs it would be the Post Office. Relatively low daily mileage that ends right back where they start.
I saw a test vehicle on a mounted USPS route a few years ago. No wasteful idling like the gas trucks. Current EVs have regenerative braking which recovers energy and spares brake wear. Far fewer parts to maintain. I have friends with Teslas, their idea of routine maintenance is filling the windshield washer fluid.