Even though they buy with KYC only the exchange knows who/whale bought/owns the BTC, it's very likely that the exchange won't open this data and is quite doubtful that whales will buy it through the exchange because they could buy through other methods.
Addresses detected as having a lot of BTC are mostly exchange addresses, so it is very difficult or impossible to reveal how many whales have BTC or how much they have because their decision to own btc is anonymity.