Because all exchange platform need to the personal info.
Also I can't buy huge amount bitcoin and altcoins via the platforms.
You can use DEX if you won't to provide personal info or deal with someone to trade p2p using escrow, you can find escrow list here:
https://bitcointalk.org/index.php?topic=2439910.0I'm not sure there are people who willing to trade huge amount. Unless you deal with the exchange.