Remember: Visiting the Dome of the Bundestag is free, but you have to register beforehand: https://www.bundestag.de/en/visittheBundestag/dome/registration-245686 Last admission is 21:45 which is nice, since you can visit after the conference and after sunset.

my favorite museum is https://en.m.wikipedia.org/wiki/Neue_Nationalgalerie. Also well worth it for the architecture imo.