After https://github.com/bitcoin/bitcoin/pull/27037 miniscript is extracted from compatible scripts, unless the `FillableSigningProvider::AddCScript` check for `MAX_SCRIPT_ELEMENT_SIZE` fails, which then it falls back to legacy behavior.

@achow101 
this_prop.pushKV("key", HexStr(entry.key));
        this_prop.pushKV("value", HexStr(entry.value));
        proprietary.push_back(this_prop);
    }
    result.pushKV("proprietary", proprietary);
    
    UniValue unknowns(UniValue::VOBJ);
    for (auto entry : psbtx.unknown) {
        unknowns.pushKV(HexStr(entry.first), HexStr(entry.second));
    }
    result.pushKV("unknown", unknowns);
    
    CAmount total_in = 0;
    bool have_all_utxos = true;
    UniValue inputs(UniValue::VARR);
    for (unsigned int i = 0; i < psbtx.inputs.size(); ++i) {
        const PSBTInput& input = psbtx.inputs[i];
        UniValue in(UniValue::VOBJ);
        
        bool have_a_utxo = false;
        CTxOut txout;
        if (!input.witness_utxo.IsNull()) {
            txout = input.witness_utxo;
            UniValue o(UniValue::VOBJ);
            ScriptToUniv(txout.scriptPubKey, o, true, true);
            UniValue out(UniValue::VOBJ);
            out.pushKV("amount", ValueFromAmount(txout.nValue));
            out.pushKV("scriptPubKey", o);
            in.pushKV("witness_utxo", out);
            have_a_utxo = true;