firefox is fine as browsers go. they've had some missteps recently with some unpopular decisions surrounding ads. brave has some controversies surrounding cryptocurrency and affiliate url links, as well as being chromium based. if those things bother you, and you are adverse to the ad issues, you could go with a fork of firefox, like librewolf.
you might communicate to your surgeon that you'd like to discuss this with your anesthesiologist, and come to an agreement that they make doubly sure that you don't respond to commands before they administer the drug that paralyzes you, to reduce the chance that this happens.
unfortunately, there's no good way to know whether you have any complications with anaesthetic until you've gone under.
firefox is fine as browsers go. they've had some missteps recently with some unpopular decisions surrounding ads. brave has some controversies surrounding cryptocurrency and affiliate url links, as well as being chromium based. if those things bother you, and you are adverse to the ad issues, you could go with a fork of firefox, like librewolf.