Most people probably want to stick with tire diameters as close to stock as possible. In terms of widths, that's really up to what you want. For EVs, the narrower the tire, the more range you get because of less rolling resistance, but also less grip because of less contact patch, given the same model tire. In terms of price, 21" tires will be the most expensive because they're very low volume sizes, then 22" and then 20" will be the least expensive.
I don't care about keeping stock diameter so I pushed it to as tall as possible without rubbing for comfort. For me, 275/55R20 for my winter set is SO comfortable and doesn't rub on anything (with ET25 offset on 20x8.5" wheels). My daily set is 285/45R22 on 22x9.5" ET25 wheels and they rub only on big bumps. They're both about 3% taller than stock with no major issues over 20k+ miles.
275/50R20 is closest to stock diameter without being too "crazy" wide. It's also a volume size so there are lots of tire options that are inexpensive.