Personally on a new build I’d go for cranks with a 1x spider or a replaceable spider that you can put a 1x spider on or get a chainring with integrated spider.
A triple works if you’re after a cheap option or want to reuse some cranks lying around. I did that initially on going 1x. I had to file down stuff to get a single ring to fit in the middle (was an FSA DH ring, not narrow wide), that was on old Truvatv GXP cranks.
Now I’ve got X0 cranks on both bikes. One was a 2x and I converted it to 1x by buying a 1x spider. The other was a 1x crank anyway. Both running Works Components narrow/wide chainrings and paired with Type 2 mechs. Medium cage on the full sus and short on the hart tail.
I think many of the SRAM GXP cranks have replaceable spiders. Not sure on other brands. Don’t have to go with replaceable spider, but it’s just more flexible. In my opinion.
Oh, and the triple does give you the option of running a bash ring. I don’t bother now as there’s no big ring teeth to grind on rocks and the chain is protecting the single ring, in a way. Chain drop is being dealt with by the narrow wide and better with a clutch.
And don’t get a double. Chain line will never be right for a single conversion. Unless the double has a replaceable spider 😉