The bike doesn’t define your use but some bikes are better suited to some uses than others. Most of my touring in the 80’s was on a road racing bicycle. I adapted my touring to what best fit the bike and fast riding, low load 10-15 lbs and bar height about 1/2” higher than what I used for racing. rear rack, medium stuff sack and camp pad, small handlebar bag. Tire size 25-28mm. But I was light with no beer belly.
Once you decide to carry rear panniers it’s worth getting a bike known to handle well with rear panniers, simply putting them on a bike that is designed to carry a rear rack doesn’t mean the bike is designed to carry rear loads well. Same with a “Gravel Bike” or cyclo-cross bike that has provisions for a rear rack.
My suggestion is to jettison your idea of picking a particular bike by it’s marketing term and get specific about your criteria. How much do you anticipate on carrying? If you do not know narrow it down. It’s like the difference between getting a F250 pickup or a Lexus sedan. You can tour on both but you wouldnt tow a 5000 lb trailer with the sedan and yould probably enjoy a more responsive vehicle if you didn’t need the trucks load carrying capability.
Second, what tire size? That varies according to road surface conditions and your total weight we could be talking 32mm to 58mm. So do you want road bike responsiveness on multiple terrain and surfaces or do you want truck like carrying capability, where shear mass precludes quick responsive handling.