I'm running Ubuntu 20.04.6 LTS and Firefox, and I find it really difficult to focus when I have the entire internet at my fingertips. I already don't use social media, but Google (or in my case Ecosia) allows me to search for whatever random thing I think of, and I end up spending 2 hours trying to work out what to cook for dinner instead of working on my PhD...

Given there's effectively an infinite number of websites, it seems like keeping a blacklist up to date would become my distraction, but from what I've seen every productivity extension and app seems to only have the option to blacklist. Very useful I'm sure if you're still stuck in the social media trap, but I am not.

Of course, I've found several ways of permanently creating a whitelist, but what I really want is one that I can set a timer on. And then I can spend 25 minutes working on writing, and only having access to ArXiv, which I very much need for research, so I can't just go sit outside with a pen and paper and call it done, either.

I'm happy to change to a different search engine if that helps, but I'd like to stay with Firefox if possible. Also, I don't want anything with a subscription (one-off payments are OK, free is better).

Cheers!