The Largest Black Holes

Lately, there has been talk of a new largest black hole, named Phoenix A*, which is said to have a mass greater than 100 billion times the mass of the sun! This is much larger than the previous record holder, TON-618. But can we really rely on this prediction? And if not, then what is the largest black hole out there, and how do we know its true size? These are the questions we will answer in search of the universe's biggest black holes.