Or viewing it differently, r there sites that provide statistics about cold wallets?
(I mean money, UTXOS, in cold wallets r not expected to be spent soon)?
There is no way to figure out which address belongs to a cold wallet and which one belongs to a hot wallet. That's known only by the owner of the address.
It should be noted that some addresses may be known to belong to an exchange or any other custodial service. But it's not possible to classify addresses into hot wallets and cold wallets.