I am building an adventure bike and want really low gearing on it for some very steep hills. I was wondering what the difference between R8020 and GRX is? What is more suitable for adventure biking? I first planned getting a RD-RX800 with 11-40 cassette and a 46/30 chainset however I was told it wouldn't work cause of the max capacity issues due to the 16 tooth difference on the front when 10 difference was the most that could fit since it has a 39t capacity. Then I saw the GRX but it looks almost the same as R8020, which brake calipers are better and which shifts better? I don't mind losing top speed if it means getting lower gearing, would it be possible to just use a 30 tooth 1x crankset and possibly beyond a 40 tooth in the rear? I just need a good set up for bikepacking/touring and need the low gearing for those very steep long hills.