The ATM’s are the most convenient way to buy anonymously, and the machines are pretty easy to use, but they’re fees are criminally high most of the time. If you’re in a major city I’d highly recommend buying privately in person through Craigslist, or sites like paxful, and search for cash in person. Having a nano S or Trezor tethered to your phone with (for example) my ledger app open, you can deposit right to the wallet. In some of these locations the atm is not in a very discrete location, so if you just want the transaction to go as smooth and fast as possible, just print an address QR code to your wallet at home, and just scan that to deposit, or have your phone open to the QR wallet address before going inside.