"any you don't recognize or need."
Good advice, keep your extensions to a minimum and there's also a thing called javascriptlets: Small scripts that can be used to replace unverified, etc., extensions or if you principally don't trust any extensions. Here is an example to increase YouTube playback speed. You can set any speed:
1. Create an empty bookmark.
2. In the "URL" field enter:
javascr1pt:(function(){document.getElementsByTagName("video")[o].playbackRate = 2.25})();(correct the 1 with an i)
3. Open any video and click the bookmark.
It may not work on other websites.
"When it comes to ad blockers, stick to well-known, open-source solutions. "
Another good advise.
"Finally, treat AI chats as semi-private services, meaning you shouldn't enter any passwords, identification details, or sensitive company data you wouldn't reveal to a stranger. "
Well, the AI company has the prompts and is going to do with them whatever they want, to a certain (high) degree, so in this sense it's not private at all. This is trivial. If you don't trust any extensions, you can create a second browser profile (firefox -p).