That's expected behavior. The feature is not yet implemented as there is a prerequisite refactor that has not been merged yet.
Thanks for the answer, I will close the github issue.
Reading the pull request you mention
https://github.com/bitcoin/bitcoin/pull/23417This allows us to have a concept of a wallet HD key for descriptor wallets. This makes it easier to add new single key descriptors that use the same HD master key as the rest of the autogenerated descriptors (e.g. for taproot). Multisigs will also be easier as an xpub belonging to the wallet can be exported without needing to do weird things like descriptor introspection and guessing about which descriptor's key to use.
Does it means that when it will be implemented it will be also easier to create a watch only wallet to create unsigned transactions? For now what I do is create a wallet offline, get the descriptors info with "listdescriptors" and export to the watch only wallet as mentioned here:
https://bitcointalk.org/index.php?topic=5392824.0 I was wondering that when taproot descriptors are added for old descriptor wallets I would just repeat the same steps, is that correct or another way to do it will be possible?