Earlier quoted context omitted.
I view using nightly to be as much of a barrier to entry that I might as well switch to a totally different browser. If the issue had lasted longer, I would have found (someone on the internet who had found) a solution like that.
On Android, you already had the xpinstall.signatures.required option without having to install nightly. Linux too. Took me maybe 30 second to fix all my devices.
Edit: on second thought, maybe I saw this solution (with or without the mention of nightly) and skipped over it as the Mozilla blog post on May 4th said "There are a number of work-arounds being discussed in the community. These are not recommended as they may conflict with fixes we are deploying."