I think the price range you're shopping clearly puts you into a carbon frame. They tend to be lighter than alloy versions and as result you somewhat defeat the point of saving weight on the frame material and than add a 2 lbs rack. I'd be doing the bike-packing bag route at that point, even though you cannot carry quite as much as with a set of good sized panniers. Attendant with the weight of a rack and larger panniers is are the wheels on a bike designed to be light-er strong enough to carry the weight of rack/panniers/gear on top of rack, etc.... ?. At some point you might want a bike-packing bike.
What are you carrying on the commute ? and how wedded are you to a rack ?.
As note about an experience with a gravel bike designed to mount a rear rack is the Cannondale Topstone aluminum I purchased last November. It's a great bike in every way. I added a 2nd set of wheels with 32mm road tires and a tighter road cassette, specifically as my "go-fast" commuting bike for when I don't need to carry commuting panniers (I have that on my touring bike). The eyelet on the frame at the rear axle is located in such away that if you install a rack, the bolt interferes with the thru axle handle. That means you have to unbolt and remove the rack at the eyelet to turn the axle handle and get the wheel off if you have a flat, OR you remove the handle on the thru axle (it's set up for removal) and use an Allen key to get the axle off. I have no intention to use a a rack on this bike so not an issue, but something to look at in terms of how and where a bike designer locates the eyelet.