The problems you're outlining are solved in chrome, and any chromium browser. I'm not saying switch. I'm saying that people have been complaining about these to Mozilla for over a decade and they won't fix it.

Most of the link based stuff is solved in other browsers by opening the link in the last active profile/window you had open. Pretty simple solution. That's all it takes, Firefox however will open links in whatever default profile you have set.. regardless of if it's open or active or not. It's a terrible behaviour. Just fixing that one thing would solve most of the big complaints people have with profiles.

I always get downvoted for saying this, but containers are not a good solution for profiles, not out of the box, and not for anyone who wants to separate work/personal.

The average user shouldn't have to install a bunch of plugins and then configure them to get the functionality that profiles gives.