Guided tours can be a great opportunity to get detailed background knowledge or to discover gems of the city you would not have ended up all by your self. On the other hand, guided tours can be tourist hell with influencing factors like group size, type of group and the factor you might have the most influence on: the tour guide
Berlins official website offers you an overview of bus and walking tours: https://www.berlin.de/en/tourism/guides/
And you might want research your tour and tourgide, i.e. on trip advisor.
Although its a biased source, it is better than knowing nothing at all (I usually read some of the best and worst comments to get an idea if the overall star ranking is credible for my ideas of a tour).
I recently discoverd that it is also worth it, to go on guided tours in the city you live in. You`ll get new insights, discover new spots and see the places your run past every day in a whole different light. Why am I telleing you this: a) try it in your home town, it might make you feel more connected to your every day environment
b) I can at least vouch for one tourguide: Tobias Allers of ‘Berlin Kultour’ https://berlinkultour.de/en/
Going on a tour with tobi feels more like a friend showing you around in his city, a friend that is a history, architecture, pop-culture, etc. enthusiast. His tours are a great mix of relaxed atmosphere and interesting stuff to learn about.
If you want to do a different than the usual tour, go on the ‘Refugees in historical perspective’ walking tour.
On last recomendation: If your are looking for a low budget bus ride along many of Berlins sights, hop on the bus 100. It´ll take you 2,80 € and about 60 minutes of your time.
In any case, I hope you`ll find a tour and a guide that suits you!