Drop bar road bike with a comfort geometry is ideal. Google the main brands for their versions of that bike type them keep an eye out for secondhand ones of them. Brands that I think are worth looking at include specialized, canyon, Cannondale, trek, Kona, Giant and possibly cube.
BTW what brand comes up my secondhand locally often depends on what is sold locally at your main bike shops. I know places where there's a big cube dealership and another where there's a Giant brand store. In those towns you see a lot of those brands and less of every other brands. Near me there's a store selling genesis, I see more of those near that store than elsewhere because of it.
Specialized is sold all over and Cannondale too. They all do good road bikes for riding on rough roads and that can take guards, wider tyres (wide as in 32mm instead of 23mm typical road bike tyres) and rack.
Happy hunting.