>So.. basically. Each window is a room space in my brain for me and I store knowledge in separated rooms, so I know exactly where the tabs are I'm searching for. It's like a library where I always can look up something. Using favorites within the browser is not possible for me, because I just forget about them. Not so if I work with all the thousands of tabs open :)

I have a similar thing.

Firefox as the main browser for everything. I don't like Electron apps and since Firefox doesn't do PWA anymore, Edge hosts all those. Chrome for all the Google apps I have to use and streaming services (Chrome has a media hub in toolbar which can control multiple streams/PiP windows).