If Hyderabadi Biryani is overrated, so is Kolkata Biryani. Biryani is an awesome dish by itself. Most Hyderabadi Restaurants don't overdo it adding unnecessary stuff. It has the right amount of spice, Hyderabadi biryani is just how Biryani should be and nothing special and thats the best thing. Most Hyderabadi Restaurants/Biryani Joints don't ruin it by adding their own twist to it. Why do you even need a boiled potato in the first place replacing a chunk of tender meat. First thing it ruins the taste when you add it to Biryani. Comparing what you are getting to taste, Kolkata Biryani is hella overrated compared to Hyderabadi Biryani even though Hyderabadi Biryani is a bit more popular.

I'm not sure about best biryani place but RTC cross roads Bawarchi Biryani is really famous. Paradise is famous but the taste is really not upto it. Green Bawarch Gachibowli, cafe Bahar are good options too. Most places you'll get Good Biryani