> Sadly the community prefers to solve this at the application level rather than the desktop level

Not only does it "prefer", they actually enforce this. I haven't found any sensible way of completely disabling tabs in either Firefox or Chromium. FF has some janky extension that kinda sorta works, but it's a hideous workaround consisting of hiding the tab bar and automatically detaching most new tabs. With the rest of the tabs, you're SOL. Haven't found anything at all for chrome.

I very much prefer managing windows with my my... window manager. Which works the same way with all applications.