This is generally a good thing to do. Also using Private Browsing mode wherever possible. Though, as you say, it can cause some issues with sites that use third-party cookies for vital functionality
Better will block a lot of trackers setting unwanted cookies, but we don’t have 100% coverage (we’ve focused on the most popular trackers on the most popular sites) so it’s good to set strict cookie preferences as a backup.
Same answer as above. Better shouldn’t block functional cookies (if you find it is, let us know and we’ll get it fixed.)
I hope that helps. Let me know if you have any more questions!