The GRX 600 is a 46/30 chainring set. Yes the crank will work with the SRAM cassette as long as you have the right hub the SRAM 11 speed 10-42 cassette requires an XD driver on the hub but most good hubs (DT Swiss etc) allow you to change out the driver for $60 or so. SRAM 11 speed 11-** cassettes use the same driver as Shimano
AFAIK.
For me, old and slow I have all my bikes set up 2x. I'd rather have the low gears and not need them than the other way around.