Originally Posted by
cpach
If this is what you really want, I'd probably just advise you to not take any shortcuts and do a 46/30 crank with an 11-36 cassette (just out of spec) with the correct derailleurs.
I'm doing this, and make significant use of that lowest gear, especially off-road. Those who say a 1:1 ratio should be good enough probably ride different conditions.
I've heard, anecdotally, that you can keep your rear derailleur and cassette and add a GRX Di2 front derailleur and a GRX double crankset, and it will work as long as you don't need the sync shifting.