How heavy is your current frame, and what road frame would you be looking at?
For instance, a Giant Revolt frameset versus an S-Works Aethos frameset is around a pound. For a 170lb road rider doing 300W on a 7% climb, the change in speed from such a weight difference will be very roughly in the ballpark of half a percent. So for instance, if the climb was an hour long, the rider would reach the top maybe 15-20 seconds sooner on the climbing frameset versus the gravel frameset.