The Outlander PHEV has been "coming soon" to the US for longer than the Model X. Until they actually start delivering them, there's no guarantee they won't delay it yet again.
I have seen the X5 40e on the road so they should be available now. While I find the XC90 T8 more appealing, the premium they charge for the PHEV seems hard to justify. The X5 40e seems to keep the price better in line with the benefit received versus other models in the line. The Build & Price has been available on BMW's website for at least a month or two now, so I'm not sure why you couldn't find it.