You are spot on with the Co-op Cycles ADV 2.2 working well for road, gravel, and light single track! The entire Co-op Cycles ADV line is designed with that kind of use in mind. The Topstone is a similarly designed line of bikes, utilizing the Shimano GRX line of gravel-specific components. In fact, in a serendipitous meeting of bikes-not-exactly-fitting-in-their-surroundings, I was at my local MTB park yesterday on my fat-tire bike and saw someone riding a Cannondale Topstone on the singletrack there. Another, similarly designed bike in that category is the Salsa Cutthroat if you'd like to check that bike out. We'll speak with our buyers to see if we'll be carrying any of those in the future as well. We'll keep you posted on availability when we have more info.
Hopefully this helps, thanks!