You mention wanting "a fast set of wheels," which tells me that you plan to hustle at least sometimes on your S40. For that I would recommend a 2x system where you have a wider gear range with smaller jumps between gears. You'll have an easier time finding the right gear for the speed you want to go, rather than being stuck between a gear that is slightly too easy or slightly too hard on a 1x setup. The simplicity of 1x is nice, but when you're riding, you want the right gear for your mood and terrain.
I have carbon go-fast 20/24 spoke wheels on my V20 and S30 with 25mm Schwalbe Pro Ones set up tubeless. They are a little fragile (but most race-ready road tires are), but for the ride quality and ease of setup I am willing to replace them a little more often. My S40 is built as my commuter and runaround bike. I built up a pair of 27.5 carbon CX wheels, 28 spokes with disc hubs, which allows me to run balloon-like 42mm Panaracer Gravel Kings. These wheels are certainly slower, but the ride is magic-carpet smooth. But I could see that if I were to put the V20 wheels on the S40, it would be a quick bike too.
After munching several pairs of aluminum wheels on Cruzbikes (and I only weigh 130 pounds), I switched over to carbon rims, which have been absolutely bombproof. They cost more up front, but at the rate that I was going through aluminum rims, I figure I've saved money--and that's with me building my own wheels.
