I was going to vote for the Roubaix with a second set of wheels for gravel riding. However,
it doesn't look like the Roubaix has much tire clearance (33 mm?). A 700x32 or 700x33 tire (if such thing exists) wouldn't be a very nice gravel tire.
Hence I voted for the Lynskey as that bike would be the most versatile of the two with two wheel sets.
My 2021 Trek Domane has 700x32 tires for my road wheels and 700x38 tires for my gravel wheels. While the latter isn't a huge tire, it's more than I've needed for the 10% of the time when I actually ride off road.
BTW, pictures of both bikes might make me change my mind
