I'm in the same boat...Sirrus X 4.0 - except I want climbing gears to go from a 40T to a 34T.
Mine came stock with the 40T and your's came with a 42T. I called Specialized and the only information I got from them was it was a SRAM X-Sync Direct Mount - But nothing on SRAM even comes close !
Seems Specialized is using a "direct mount" chainring in which I can't find any tool out there to remove it - let alone finding a chainring for it.
Looks to be a 68mm BB, 24mm spindle.
Check your front chainline...If it is like mine...then it is a 45.5mm chainline.
If that is the case then you can use a couple of different SRAM cranksets that have a 45.5mm chainline.
There is none for me to go lower in teeth, that I know of.