This was it! Took me a bit to figure out you meant the Product Menu. (I was looking in project settings and stuff.) Thanks so much for getting me going again.

Aha! Turns out I had limited architectures somehow in my Cocoapods settings; after I fixed that, I also needed to clear “EXCLUDED_ARCHS = arm64;” which had somehow crept in to my executable's project settings. That and a restart resolved it all.