If a hardware wallet is programmed to secretly transmit your seed phrase to an external server, then it probably isn't going to matter whether that seed phrase was generated on the device itself or imported from elsewhere.
Yeah, but I said that because ''random generators'' are not so random as people may think, and what is happening inside closed source hardware wallets is a secret by design.
You can always generate seed words your own and import it to hardware wallet that is not connected to computer with internet connection, so there is no way to send anything online.