No matter which web browser I use (Chromium, Firefox, Pale Moon, even in safe mode) I can't edit my profile because the site doesn't take the press of the save button in any web browser.

You have hidden your hardware - so it is not easy to help.
On the other hand, if the language ikon does not correspond to your physical keyboard, then you've only yourself to blame !

I haven't hidden my hardware and never saw a 'language icon' but write English w/USA IBM model M keyboard. Most isn't langauge like can't save new avatar, can't join a team, can't select other preferences/questions, and my profile description was erased, etc. I'm certainly not to blame; 'blame the user' is common.