This is related to #14150 and possibly others, but it's actually a separate issue.

For instance, when using the following query:
`bitcoin-cli scantxoutset start '[{"desc":"wpkh(xpubABCDEF/0/*)", "range":100}]'`
I can get a list of UTXOs, but no way to get back the index which derived that particular UTXO. So it's not much better than deriving on the user side and specifying addresses one by one, so that I already have a cache of addresses to match.

Not sure what the solution looks like. One way is to repeat the full descriptor in the utxo. That might get verbose though.
"  \"complete\" : true|false,   (boolean) If the transaction has a complete set of signatures\n"
            "  ]\n"
            "}\n"
            "\nExamples:\n"
            + HelpExampleCli("walletprocesspsbt", "\"psbt\"")
        );
    RPCTypeCheck(request.params, {UniValue::VSTR, UniValue::VBOOL, UniValue::VSTR});
    
    PartiallySignedTransaction psbtx;
    std::string error;
    if (!DecodePSBT(psbtx, request.params[0].get_str(), error)) {
        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
    }
    
    int nHashType = ParseSighashString(request.params[2]);
    
    
    const CTransaction txConst(*psbtx.tx);
    
    bool sign = request.params[1].isNull() ? true : request.params[1].get_bool();
    bool bip32derivs = request.params[3].isNull() ? false : request.params[3].get_bool();
    bool complete = FillPSBT(pwallet, psbtx, &txConst, nHashType, sign, bip32derivs);
    UniValue result(UniValue::VOBJ);
    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
    ssTx << psbtx;
    result.pushKV("psbt", EncodeBase64((unsigned char*)ssTx.data(), ssTx.size()));
    result.pushKV("complete", complete);
    return result;
}
UniValue walletcreatefundedpsbt(const JSONRPCRequest& request)