Go for a gravel bike with shorter chainstays, and maybe get a second wheelset with narrower tires like some suggested if you will find 40mm or wider tires to slow for pure pavement rides, but it think you can ride with wider tires without problems on pavement, be fast and also be more comfortable as someone on dedicated road bike with 28mm tires. I know for sure i will never go back to those skinny tires! Best would be if you could get a test ride before making an investment.