You keep talking about HD wallets, and I want to stress that both legacy and descriptor wallets are HD wallets. There is no way to create a non-HD wallet in Bitcoin Core. Regardless of whether you make a legacy wallet or a descriptor wallet, you will be making an HD wallet. Being HD or not is not really relevant to your question.
Hello achow101Thank you for your patience. Yes, I thought hd wallets and descriptor wallets were synonyms. Now I understand it better. So excuse my ignorance.
If you really want to have a paper backup, it is possible to do this with descriptor wallets by using the RPC listdescriptors true. This will output all of the descriptors in the wallet (there aren't many) with their private keys included. You can write that down on paper if you really want to. Note that it is case sensitive. Also, you can't do this with legacy wallets.
Thank you. That is already close. I have experimented with it and also used "bitcoin-cli getaddressinfo". To calculate the missing private keys in the hdkeypath I therefore followed these instructionshttps://bitcointalk.org/index.php?topic=5351210.msg60007045#msg60007045
The tool calculates the public key for my test address in the keypath correctly but shows another bitcoin address.
I will research further there. But if you have any idea what could be the reason, please let me know.
You have helped me enough as it is. Thanks again for that.