During 2020 I built up a bike with a SRAM Eagle 10-50T twelve-speed cassette ...
I've been assured that this 1x12 gear range is ridiculously inadequate for touring. ....
I would call that a low end for desired range for touring, but not inadequate. A 1X with a 10/50 cassette gives you a 500 percent range. My Rohloff bike has a range of 526 percent, which is only slightly better.
But I have often wished that my Rohoff bike had more gearing up higher for shallow downhills, but I am unwilling to give up my low gearing to obtain that higher gearing. Thus, I wished my range was a bit greater than 526 percent.
My derailleur touring bikes are 558 percent, I consider that better. I had a bigger big ring that gave me even greater range, but I reduced the range to get more mid range gearing.