If the narrow wide works then it should do all the heavy lifting, the clutch mech just helps control the chain a little. But still worth it I reckon just for quietness.
I’d go Shimano, personally. Shimano weren’t subtle about ripping off all the things that 9-speed SRAM did better, and their build quality was always a step above, so it’s a winning combo. XT is a really nice bit of kit, well judged, and durable and Saint is imo the best shifter ever made, so… That.
Do keep the receipt though, I think there’s been a rolling revision now which might have fixed it but earlier ones were known for breaking their clutch mechanisms. No biggie- the mech still worked as a normal mech and Shimano replaced them without any fuss, it’s a 5 minute job to swap the broken bit. But still.