Originally Posted by u235

FSA omega crankset supports a 30/46. Overall setup is realtively cheap compared to other options. I've been running this 6 of my last 10k miles with the same cranks and BB with no problem and most of that is in gravel, grit, and moisture (along with a 36 or 32 big in the rear). I am not light and I've done many trips with various touring gear strapped on. I can't speak for different front derailleurs but I have a CX70 and it works perfect with both a Tiagra 34/50 HT2 and my FSA 30/46 that I swap around.
General notes for this option..
- You can get the Omega with 34/50 and swap to FSA 30/46 rings or just get the FSA Omega "Adventure" which come with 30/46. The price is about the same for either route as the 50/34 seem to be cheaper and more readily available last I looked.
- There is exactly one and only one BB choice for the Omega cranks and 68 shell, a BB-4000 (cranks are Ø19mm spindle, not ~24 like the HT2 and similar). It costs more than a HT2 and probably not on the shelf at many LBS but it does seem to last.

EDIT: I did not know the GRX 30/46 was as cheap as it was, I must not have looked in a while. If you have the front der and the shifter pull ratio already if required, seems to be a great option.