HD vs non deterministic:
"HD" means "hierarchical determinist".
"deterministic" means: all private keys are generated from a seed, "know the seed = know all the private keys", so that a frequent backup is no longer necessary.
"Hierarchical" means: You can manage multiple types of parts / accounts / addresses with a single seed. Only monitoring portfolios are expected to import only the extended public keys from the account, instead of the primary public key, so that, even in the case of security breach, the enhanced parent nodes can protect the other accounts against piracy, provided that the primary private key is not a leak.
HD only affects how your private keys are generated and how you need to back up your wallet. This has nothing to do with how you broadcast a transaction, nor with your IP address.
Bitcoin-QT was once a non-deterministic portfolio: all private keys are generated independently. This can be true even if you are using a modern version of Bitcoin Core (which supports HD since 0.13) because Bitcoin Core will not upgrade an inherited non-deterministic version.
wallet.dat HD automatically. You can upgrade it manually by restarting Bitcoin Core with
Upper class command line argument – of course, you have to back up your wallet once more after this operation. BTW, if you have enabled wallet encryption, or run something like
sethdseed in the console, you must also save it again.
However, Bitcoin Core uses a stronger address gap, which means you can not export any files.
XPUB public key extended to a portfolio reserved for watches. Moreover, Bitcoin Core does not provide any mnemonics.
Full node vs thin client
Full-node portfolios such as Bitcoin Core rebuild the balance of your portfolio and the history of your transactions by analyzing the entire blockchain again. locally, so the reception privacy is almost perfect.
Thin clients like Electrum ask other people the history of your transactions and the balance of your portfolio, so there is inevitably leaks in terms of privacy. However, Electrum uses TLS to encrypt the traffic, so your ISP / public WiFi provider / etc does not know the history of your transactions and the balance of your wallet. You can use Tor to hide your IP address, but the Electrum server is still able to register addresses that have a common owner.
BTW: Electrum servers are not controlled by the developers. Anyone can run their own server to join the network.
With regard to sending confidential data, the Electrum server you use obviously knows your IP address and the transaction you are broadcasting. However, because your connection to the Electrum server is encrypted by TLS, intermediaries such as your ISP can not detect the transaction you are sending.
Bitcoin Core relays other default transactions, making traffic sniffing a little tricky, but not impossible. Anyone who is able to monitor your Internet traffic, including your ISP / public WiFi provider / etc, is also able to know which transaction is sent by you. Therefore, to protect the confidentiality of your shipment, you can use Tor to serve your gross transaction (you can use the Tor browser with an online block browser service that supports transaction delivery, such as -this).
Using Tor with a complete knot is still not enough
All transactions in bitcoins are public information. You can learn more advanced techniques to further protect your privacy: https://en.bitcoin.it/wiki/Privacy