Any update on this one? Those feedback assistant links show nothing for me, fyi. (Yes, I'm logged in, and yes, I'm a registered Apple Developer.)

Hmm.... I have your problem in reverse. I'm getting that same "library not found for -lDoubleConversion" error when I try to build for the iOS Simulator, either from the terminal or running directly in XCode. But the error doesn't trigger when I build an Archive in XCode. Mine is an M1 (Apple Silicon) Mac. Is yours?