A gravel bike on GP5000's is likely about as fast a setup, given what was pictured, than some folk's older road bikes on pretty generic road tires and box rims. Not everyone on an A ride is on a Venge/Propel/Timemachine with deep dish wheels and aero/race geometry and fit.
In fact, those tires on CRR alone could be up to 10w+ per tire faster than another road tire. So 20w faster.
If you came in saying you went off the front, solo, for a 1/2 hour before getting caught on the gravel bike and were rocking 32mm+ gravel grinder tires at a minus 10 to 15w penalty per tire then I'd have been more impressed.
I've brought the CX bike to the A ride before thinking it was gravel night. Oops. Did just fine, could break away when the road grade went positive just fine. The 1x was annoying trying to go downhill.
If you want to prove it's really the engine, try it again on your gravel tires and try to stay at least a 1/4 mile off the front solo for at least 1/2 hour or so. Not cheating a stop light or some crap either.
If you can........then you're at the wrong group ride.
Everybody knows that a mixed surface geometry drop bar bike with road tires does the job 99% as well as a dedicated road machine does. That's not a revelation.