I used to bookmark everything into Diigo. Then their Firefox extension stopped working... and I haven't got a cross-platform, cross-browser process up and running again.
Is there a tab session manager that does that, and lets me send tabs from my current session to another session? E.g. I'm on my "Writing C for a hobby" session and quickly search for something cooking related, and then need to send that to my cooking session?
757 is too many though. If nothing else, if you couldn't find an extension that works, you could just use different browser profiles, or save the links in text files. It's just so ridiculous to have that many open when, without any doubt, you don't need them open all at once.
I use tab session manager on firefox. It doesn't easily let me shift around tabs inside a session, if I want to combine sessions I have to open both and save as a new session. It does allow duplicating and trimming tabs from a session though.
If you need better session management capability, you could probably get an LLM to extend/fork an existing extension to add what you need with about 30 minutes work.
Firefox copes fine. Me? Not so much (: