I personally think you would be better off starting out with a road bike, and converting that to a gravel bike. 70's and early 80's Raleighs and Peugeots are undeniably credited road bikes, with road bike geometry, often being built with Reynolds 531 or similar high-grade tubing. Many of them also have very generous tire clearance, as an added bonus, being designed to take fenders for muddy European roads.
Below is my 1976 Raleigh Competition, in Reynolds 531, with 700x38 tires.
