I have a Moots Routt RSL. I got it strictly as a gravel bike in 2018 and have found myself riding it more and more on the road. In fact I sold my Tarmac SL7 this spring and now have the Routt as my only drop bar bike. I could definitely tell a difference on climbs between it and the SL7 - especially short steep stuff - but not so much of a difference to justify keeping both bikes.
If I had it to do over again though, I’d strongly consider the Moots Vamoots RCS. I’d likely be willing to sacrifice some tire width for gravel rides to have more of a road geometry since this has turned into a bike I ride on the road 99% of the time.