I got it work too but wouldn’t call it easy. My process involves going to about:config to enable some variable that has a super long name. Then find out where the profiles are saved and remember not to use the “cached” directory version which I always end up on first. Then selecting one of the cryptic profile names and creating some specific directory structure and copying or linking (but no soft linking) my config there.

A simple checkbox in the settings would be nice, or another browser extension. Or is there an easier process?