Gravel drivetrain and tire recommendation

[p nut]

I've got a frame I'm building up. Steel, canti brakes, with clearance of 42c (so the builder says). I'm located out West and will be riding on typical terrain out this way. Usually, dry, hardpack, some chunk. Basically, see footages from Crusher in the Tushar, or Rebecca's Private Idaho. A nice tubeless tire to ride terrain like that. I'm thinking Gravel King at this point.

So far, I have the following:

WI hubs (Shimano 11s) to Pacenti SL23.
Paul Mini-motos F&R

I would like to stick with Shimano for this build. I like Campagnolo; however, I have heard they don't play well with Paul brakes. Besides, the wheels are already set up for Shimano. Plus, read further...

I've used 5800 and they were good. Just had to deal with chainslap. Which is why I am wondering about going 1x. 46T ring up front and XT 11-42 (or 46) in the back with XT derailer w clutch. I have heard Wolftooth Tanpan works great. I'll lose a bit of top range, but won't be too bad, I don't think. If I do go this route, what to do with the left shifter? Can you gut a Shimano shifter?

Thanks for any suggestions.