Proton passkeys are stored in a password manager, which he specifically calls out.

If you have a password managed and know how to use it, you’re already a lot less susceptible to the problem that passkeys are trying to solve.

Personally, I think passkeys are great for tech-savvy users, but I wouldn’t dream of recommending them to non tech-savvy people. Password managers are still used by the minority, that needs to be fixed before passkeys are useful.

You’ll find that under settings -> customise -> swipe address bar sideways to switch tabs

Red dwarf did it first

https://www.youtube.com/watch?v=LRq_SAuQDec

Changing your user agent will not stop you being tracked. Browser fingerprinting can work with heaps of different signals, and is very difficult to block.