I go by: If you are not sure you need a good one, buy the first one for cheap. Of you break it, buy a quality one. You obviously need it.

There will always be new malware. Just update regularly and use your head. Don’t worry about it too much

You could also ise a library. The ones I have used are free or almost free

You can disable it in the menu that opens when you click on the button at the right of the address bar

Brother ist the way to go. Also OK for Linux in my experience