My questions
~Are there private individuals who own and posses such amount of Bitcoin?
Whales do exist and I think whales do have a lot of bitcoin and an example is Michael Saylor's. I think Michael Saylor's has even more bitcoins. But we also have to know that most likely the whales will definitely save or spread their bitcoins into several wallets or dozens of wallets. and it is not possible to store them in one wallet. and if you find a wallet with a large number of bitcoins in one wallet as you show. then I think it is a wallet belonging to a centralized crypto exchange like binance. and it is common to find CEX wallets that hold many bitcoins belonging to CEX users themselves.