I once went for Brunch on a Saturday morning at Café Bleibtreu in Charlottenburg. It took me about 1 hour to get there and it was worth it. For about 9€ you get access to the buffet that includes orange and apple juice. The buffet is nice and kinda tradittional, eggs, pastas, charcuterie, cheeses, cereals, dessert,… There’s a terrace on the sidewalk but since it’s not a passing street, it can be nice. The Brunch is available on both Saturday and Sunday mornings.