> Firefox's containers is also a poor man's version of Chrome profiles. I want completely separate _everything_. Firefox's Profiles is similar, but then you get

> Firefox's containers is also a poor man's version of Chrome profiles. I want completely separate _everything_. Firefox's Profiles is similar, but then you get warnings about Firefox already running when you click a link in a non-Firefox program. Containers is solving a different problem than you have. If you have multiple profiles running, how do you want it to know which in profile to load the link? You could set your link helper in your OS to run Firefox with the --profile option, to pre-set it, if that's what you want.