as a example: imgur.com/a/VBnr9V6In this example the top and bottem black bars are rather small but i have movies which take up almost half the screen using those bars. The left and right black bars i am fine with. thats due to my monitor being ultrawide (5120x1440)
I play the videos on my PC with jellyfin media player. But it also does this in any browser.
Their are not many programs that require open ports for incoming trafic. Things like ssh or a web server do. But then again those are services you would manualy want to open anyway.
Honnestly. Firewalls shut be enabled by default. Specially on laptops connecting to public places.
A good default shut be choosen by the disteo maintainer. A default shut not overwrite your own config. Like any config really. So no upset folks that like to change the firewall. Also if you dont block much outgoing trafic you are not likely to run into problems. And for people that like to poke holes in the incoming trafic. Your a “advanced” user anyway.