I am not an expert on Bratwurst but konnopke is one of the most renown. Gerhard Schröder (former German Chancelor) used to get his Bratwurst there:
https://www.konnopke-imbiss.de/de
It is also not far from Mauerpark (used to be Part of the Berlin wall, now a recreational area with flea market every sunday, including loads of musicians and artists around.
I am not that big on “traditional” german beer halls in Berlin, but thats proabbly because of my Bavarian heritage, that let`s me avoid any non Bavarain beer halls. You might want to check out Pratergarten a nice Biergarten (“outside beer hall”)
or Schleusenkrug