Good advice given so far! Exhaust the used bike market first. If you are tall chances are slim on finding a bike that will fit you. They are few and are not long on the market.

For the distances you are considering, get something with drop bars. A headwind will make you cry for mommy on a comfort bike. I know headwind.

Have a plan for disaster mid ride. This means a nearby access to buses that can carry bicycles. Or, have someone reliable committed to picking you up. Cellphone.

My commuting bike is a cyclocross frame and fork with 32mm tires, tireliners, discbrake and rack. I had to order all the parts and assemble it myself. I could never find a decent used road/touring etc. bike for someone my size. I looked. Get the biggest tires that will fit.