> The max I have got is around 200 tabs and even that was a considerable stress on my brain.

Here's the trick I think:

I and many others use tabs to offload the brain. For those who have read "Getting Things Done" I think this is similar.

We don't think about them, just look them up if and when we need them.

Kind of the same way as a journal or notebook: it doesn't stress me that I have hundreds of pages I might never get back to; it eases my mind that if I need to get back it is still there.

I use Tree Style Tabs and a couple of extensions on top of that so sometimes I'll copy a subtree as a nested markdown list and store it in Joplin, then close it.

But no: 600 tabs like I've had more than once was totally feasible years ago and should be no match for a moderns system.

That said as long as people don't try to force me to change the way I work they are free to do it their way.

He is using a fork of old FF which is able to run most of the good extensions which won't work with current FF. And have no equivalent there. Something like Tabmix+ comes to mind, and/or vertical tabs, several forks of Scratchbook+ also. Maybe combined with a theme like Witehart with FF you could have a very relaxed browsing experience.

That is all gone, FF has been dumbed down, and Chrome(ium) even more so.