Agree about the tires making the biggest difference in how smooth a bike rides. Three years ago I bought a Lynskey road bike. Fit it with 700x32 tires. It was like the cracked and pot holed roads here in northern New Jersey had been repaved. Retired my carbon road bikes that maxed out at 25mm, but also bought a carbon gravel bike that clears 37s for riding on gravel roads in the Berkshires. I like the titanium but I had a cracked head tube on an older Lynskey that was repaired under warranty. Also had a crack in the seat tube of a CF Specialized Roubaix that was replaced under warranty. Anything can break. Regular cleaning and inspection are mandatory. Any squeaks or unusual noises should not be ignored. So I would recommend considering any frame material but go with wider tires and whatever makes you smile.