Steps to reproduce on regtest:

```
converttopsbt 02000000000101ab73dba46508bacdb49a988ddd74bc9d39c9cb7e057af060ca8c6b6861e28e3c0300000000feffffff02b828d0b20000000017a914d1954862afd728fbb055149002958e1d1b9e1f0b8700ca9a3b0000000017a91442170ccb3441cff1723af9afab6f2553103e1d578702473044022077380c6e16496d9905aef120694c329be51522847cb5d53fa74b94698c95678d02202d32c46e0e17420a83dee830fefda7d40529182f5d82be47c2b49a7b83214ab50121026d483d6628dcc3ef6e3ab9ed4937c452c263c7e0ac80eb4be97426d5da8f640500000000
```
or 
```
converttopsbt 02000000000101ab73dba46508bacdb49a988ddd74bc9d39c9cb7e057af060ca8c6b6861e28e3c0300000000feffffff02b828d0b20000000017a914d1954862afd728fbb055149002958e1d1b9e1f0b8700ca9a3b0000000017a91442170ccb3441cff1723af9afab6f2553103e1d578702473044022077380c6e16496d9905aef120694c329be51522847cb5d53fa74b94698c95678d02202d32c46e0e17420a83dee830fefda7d40529182f5d82be47c2b49a7b83214ab50121026d483d6628dcc3ef6e3ab9ed4937c452c263c7e0ac80eb4be97426d5da8f640500000000 false
```

Further reading: #13738
{
    if (request.fHelp || request.params.size() != 1)
        throw std::runtime_error(
            RPCHelpMan{"decodepsbt",
                "\nReturn a JSON object representing the serialized, base64-encoded partially signed Bitcoin transaction.\n",
                {
                    {"psbt", RPCArg::Type::STR, RPCArg::Optional::NO, "The PSBT base64 string"},
                },
                RPCResult{
            "{\n"
            "  \"tx\" : {                   (json object) The decoded network-serialized unsigned transaction.\n"
            "    ...                                      The layout is the same as the output of decoderawtransaction.\n"
            "  },\n"
            "  \"unknown\" : {                (json object) The unknown global fields\n"
            "    \"key\" : \"value\"            (key-value pair) An unknown key-value pair\n"
            "     ...\n"
            "  },\n"
            "  \"inputs\" : [                 (array of json objects)\n"
            "    {\n"
            "      \"non_witness_utxo\" : {   (json object, optional) Decoded network transaction for non-witness UTXOs\n"
            "        ...\n"
            "      },\n"
            "      \"witness_utxo\" : {            (json object, optional) Transaction output for witness UTXOs\n"
            "        \"amount\" : x.xxx,           (numeric) The value in " + CURRENCY_UNIT + "\n"
            "        \"scriptPubKey\" : {          (json object)\n"
            "          \"asm\" : \"asm\",            (string) The asm\n"