bitcoin cli – Unable to generate address after importing Taproot multisig descriptor

I have 3 wallets that I use to create a Taproot multisig wallet. All my work is based on this https://github.com/bitcoin/bitcoin/blob/master/doc/multisig-tutorial.md. Here are the external and internal xpubs for each one:

Wallet 1 (external + internal xpubs)

[11776e3b/86h/1h/0h]tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/0/*
[11776e3b/86h/1h/0h]tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/1/*

Wallet 2 (external + internal xpubs)

[fe5187e5/86h/1h/0h]tpubDCqr5GVKeptzMG5QKLu1aQKXFXgF6kMy9dYDQ6Nap6emZ3iziMCeVX1pPjEzA7nTmyZS9NP2KjUsGtEs8jNqFcUTpKxAwXPB3yfbee4RthM/0/*
[fe5187e5/86h/1h/0h]tpubDCqr5GVKeptzMG5QKLu1aQKXFXgF6kMy9dYDQ6Nap6emZ3iziMCeVX1pPjEzA7nTmyZS9NP2KjUsGtEs8jNqFcUTpKxAwXPB3yfbee4RthM/1/*

Wallet 3 (external + internal xpubs)

[9f5cbc68/86h/1h/0h]tpubDDQbi15GQjXYxhAysxdEC6VsSFacJ6hgDAJ7oQy4wUs9sfwMQWtcLqLx7GUbBfWyVwUYMEEJtWmxFXmpmjQL8X4cRdgAJ7BcaazuCYq4iCp/0/*
[9f5cbc68/86h/1h/0h]tpubDDQbi15GQjXYxhAysxdEC6VsSFacJ6hgDAJ7oQy4wUs9sfwMQWtcLqLx7GUbBfWyVwUYMEEJtWmxFXmpmjQL8X4cRdgAJ7BcaazuCYq4iCp/1/*

Here is my descriptor:

external_desc="tr(tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/1/*,sortedmulti_a(2,tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/0/*,tpubDCqr5GVKeptzMG5QKLu1aQKXFXgF6kMy9dYDQ6Nap6emZ3iziMCeVX1pPjEzA7nTmyZS9NP2KjUsGtEs8jNqFcUTpKxAwXPB3yfbee4RthM/0/*,tpubDDQbi15GQjXYxhAysxdEC6VsSFacJ6hgDAJ7oQy4wUs9sfwMQWtcLqLx7GUbBfWyVwUYMEEJtWmxFXmpmjQL8X4cRdgAJ7BcaazuCYq4iCp/0/*))#546p4cqh"

For the first argument of tr I use the internal xpub of wallet 1, and I use sortedmulti_a to configure my 2-3 using the external ones. The I call the getdescriptorinfo command:

 ./build/src/bitcoin-cli -signet getdescriptorinfo $external_desc
{
  "descriptor": "tr(tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/1/*,sortedmulti_a(2,tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/0/*,tpubDCqr5GVKeptzMG5QKLu1aQKXFXgF6kMy9dYDQ6Nap6emZ3iziMCeVX1pPjEzA7nTmyZS9NP2KjUsGtEs8jNqFcUTpKxAwXPB3yfbee4RthM/0/*,tpubDDQbi15GQjXYxhAysxdEC6VsSFacJ6hgDAJ7oQy4wUs9sfwMQWtcLqLx7GUbBfWyVwUYMEEJtWmxFXmpmjQL8X4cRdgAJ7BcaazuCYq4iCp/0/*))#546p4cqh",
  "checksum": "546p4cqh",
  "isrange": true,
  "issolvable": true,
  "hasprivatekeys": false
}

And I use that descriptor to build the descriptor JSON used to import it into my wallet.
This is what I used to create the json:

external_desc_sum=$(./build/src/bitcoin-cli -signet getdescriptorinfo $external_desc | jq '.descriptor')
multisig_ext_desc="[{\"desc\": $external_desc_sum, \"timestamp\": \"now\"}]"

After that, I call the importdescriptors method on a new blank wallet:

./build/src/bitcoin-cli -signet -named createwallet wallet_name="multi_tr" disable_private_keys=true blank=true
./build/src/bitcoin-cli -signet -rpcwallet="multi_tr" importdescriptors "$multisig_ext_desc"
./build/src/bitcoin-cli -signet -rpcwallet="multi_tr" getwalletinfo

The response of the import descriptors is:

{
  "name": "multi_tr"
}
[
  {
    "success": true,
    "warnings": [
      "Range not given, using default keypool range"
    ]
  }
]

And the output of get wallet info is:

{
  "walletname": "multi_tr",
  "walletversion": 169900,
  "format": "sqlite",
  "balance": 0.00000000,
  "unconfirmed_balance": 0.00000000,
  "immature_balance": 0.00000000,
  "txcount": 0,
  "keypoolsize": 0,
  "keypoolsize_hd_internal": 0,
  "paytxfee": 0.00000000,
  "private_keys_enabled": false,
  "avoid_reuse": false,
  "scanning": false,
  "descriptors": true,
  "external_signer": false,
  "blank": true,
  "birthtime": 1739107662,
  "lastprocessedblock": {
    "hash": "0000005ba71046c3e13011955cf5a65c09fc7e945030a3d623dbfef8e7b3dce6",
    "height": 234655
  }
}

After seeing this output I was excited and I wanted to generate a new address to funds my multisig wallet, but I got an error:

./build/src/bitcoin-cli  -signet -rpcwallet="multi_tr" getnewaddress
error code: -4
error message:
Error: This wallet has no available keys

After looking for alternatives, I found that the deriveaddresses method works for my use case and I was able to retrieve some addresses:

./build/src/bitcoin-cli  -signet deriveaddresses "tr(tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/1/*,sortedmulti_a(2,tpubDCTp9moNmiVHK9KS6j6HEyU9duvomZrE87wTNQMkcZktDu89f3yJFATEQovpsT8KwUDWhut5YYd3zNsUYuv6sGHLozsub1AHPoyL7uGW2LT/0/*,tpubDCqr5GVKeptzMG5QKLu1aQKXFXgF6kMy9dYDQ6Nap6emZ3iziMCeVX1pPjEzA7nTmyZS9NP2KjUsGtEs8jNqFcUTpKxAwXPB3yfbee4RthM/0/*,tpubDDQbi15GQjXYxhAysxdEC6VsSFacJ6hgDAJ7oQy4wUs9sfwMQWtcLqLx7GUbBfWyVwUYMEEJtWmxFXmpmjQL8X4cRdgAJ7BcaazuCYq4iCp/0/*))#546p4cqh" "[0,2]"
[
  "tb1pg0p5p2vfqn3stjrrz0ga33m4wudcxmsl4qsuv4csnq5lxfnws3zss5xcvh",
  "tb1p4z6n9hlt2rs9arlaxwkcgpp79803rmle6wty946zwce74u4wnmas4r8etx",
  "tb1pk3nj9xt2aempeys63etmw3zfkj8pya0sr2lcl2spf6xqtjev8zfqkfzg5p"
]

my questions are:

• Why the first method to generatenewaddress is not working?
• Is the deriveaddresses method recommended for general use? If so, I think I will need to save the used range to generate new addresses every time (because using the same range twice generates the same addresses). So if I use the range [0,0], the next time I will need to use [1,1] and so on.

Thanks