If your wheels are deeper, with a gravel friendly cassette and tires, a switch to lower profile rims, an 11-30 cassette, and Vittoria Corsas could net you similar weight savings, with much less work involved than a frame swap.
I have an 18 lbs, semi-weenie-ish bike, and a nearly 21 lbs bike. The 18 pounder is definitely more fun when I’m slicing through traffic - the lighter bike, and lighter wheels make short sprints easier. However, on the limited climbing that I do (nothing more than about 1/3 mile on my normal routes, sadly), the 18 lbs bike only holds the KOM for one of those climbs. Granted, these are short, 1-3 min climbs, but the difference in either direction is only 1-2 seconds between the best time on one bike vs the other.
Not saying you shouldn’t go for the lighter bike - it’s definitely fun to have something feel more tossable. I just wouldn’t want to do a full component swap (read: lots of work), expecting performance gains, only to find them to be marginal.