I have been using a 20x22 for more than 20 years. I keep two cars in it, drivers, not projects. So it’s been a nuisance because I have always had to hurry the jobs up to get cars in out of the weather.
I’m now building a 24x28, should get finale in a couple weeks, and will just use the 20x22 for two cars and a little storage.
My experience with the 20x22 is that it works, has room to park most vehicles (trucks, Cadillacs) over the years and with a LOT of organization you can get a lot of tools in with the cars. If I was willing to park all the cars in the yard it would have been enough for most projects.
You have to be VERY organized to use a smaller garage. The big garages I am in are usually very cluttered, often full of things from the house, or projects that should have been abandoned or finished years before.
I think the larger storage lets you get sloppy, but it makes for lots less rushing and less stress to wrap the jobs up.
On any garage, getting it deeper than 20 feet is essential if you ever park a truck or long car in there.
I would rather have deep than wide, up to about 24, then you can park most trucks and still walk around them.