I have found websites like these where they talk about Xbox Live ports but nothing Battlefield specific: https://portforward.com/battlefield-2042/
1) Are there no additional ports needed besides the Xbox Live Ports?
2) I can find anything on the official website. Is the information still unclear by the devs or in test fase?
3) Are there other router/network requirements (like UPNP)?
Community ManagerI will leave the info for other platforms for the benefit of others reading this, thanks.
http://help.ea.com/en-us/help/faq/connection-troubleshooting-basic
https://help.ea.com/en-us/help/pc/connection-troubleshooting-advanced-pc/
http://www.help.ea.com/en-us/help/console/connection-troubleshooting-advanced-xbox
http://help.ea.com/en-us/help/console/connection-troubleshooting-advanced-playstation
https://help.ea.com/en-us/help/faq/opening-tcp-or-udp-ports-for-connection-issues
