Hard to understand how 50c tires at low pressures isn't comfortably, but with that said comfort is subjective. If you only road ride 4 times a year yeah ditching the road bike might make sense but I am kind of more interested on what kind of gravel you ride where 50c tires just don't just cut it. I think at this point if large tires aren't doing the trick than a gravel bike with mechanical dampening like the Roubaix or even the Diverge STR might make sense.