The next problem is the private key obtained through the BIP39 tool, which, in my opinion, will eliminate the function of the wallet descriptor, for example, when it is reused in the recovery process via the importprivkey command.
Yep, I read the article from achow101's blog:
What's Coming To The Bitcoin Core Wallet in 0.21, What I understand from the article is that the wallet descriptor uses a script system while the previous bitcoin core wallet used privatkey, I don't know which is the best between the two and what is the reason for the bitcoin core developer to remove privatkey in the wallet descriptor. Also, wallet descriptor is the default option in bitcoin core for now, so I think bitcoin core developers suggest to create wallets in the form of wallet descriptor
I hope @achow101 is willing to explain in more detail regarding this issue and use a third party to see the private key of wallet descriptor is safe or not.