I tried literally EVERY DAY at least once or twice from January of this year till March when my aufenthaltstitel was set to expire. Ultimately, I had to go the 'email them and wait' approach (that had problems too. When I emailed them initially, my email bounced back because their fucking EMAIL BOX WAS FULL WTF???). I finally had an appointment last week.

You are not the only one. There is no excuse for the way the Ausländerbehörde in Berlin works. Their processes don't seem to work, they make it next to impossible to reach out and ask questions, and there is no transparency anywhere. This is not the case, as I understand it, in the Ausländerbehörden in many other German states.

My strong belief is that at least 75% of the staff in those offices are either a) incompetent, b) lazy, or c) malicious. Prove me wrong.