I personally have this: https://www.specialized.com/us/en/air-tool-big-bore-pump/p/156235?color=229150-156235
I am vary happy with It. I also only right fat bikes at the moment and this fills it up fast with no problems. As for wait, I mount it with the included mount beside the water bottle cage on my down tube and have never even noticed it was there.
I think CO2 has it’s place, like in a race, but a nice high volume pump like this can some times be just as fast or very close. So long as we are not talking minutes in the difference I like having the pump over the CO2.