My wife has a 2020 Domane SL5, which we both test rode against many of the other endurance bikes, e.g., Roubaix. She wanted comfort, first and foremost, and the Domane is great in that respect. I don't think you'll be disappointed.
The Domane is perfectly capable as a gravel bike. I test mounted 45 mm WTB Riddlers (a gravel tire) and, at least on a size 54, these tires fit fine. If you need a gravel tire larger than 45, I'd rather be on my XC mountain bike. Perhaps the only downside as a gravel bike is that the gearing isn't a short for hill climbing, but that can be fixed easily by changing out the crankset.