I can assure you from experience that creating a HD Wallet in Bitcoin Core from the BIP32 Root Key works with the method I explain...
[/quote]That will certainly work when importing master private keys to Bitcoin Core. (I've been suggesting descriptors ever since it's implemented)
But you certainly didn't read the whole topic or at least OP's replies which is why I explained why simply importing the xprv key wont work in OP's case.