In my view, the decision starts with the kind of terrain you hope to explore. If you’re going to be out in single track or really rocky paths, you’re going to want at least 2” wide tires or more. In the vintage world, that likely means a mountain bike of some sort. I did a multi-day bikepacking tour last summer, and my 650b x 48mm tires were definitely not wide enough for the particularly gnarly paths.