### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current behaviour

See inline discussion at https://github.com/bitcoin/bitcoin/pull/26467#discussion_r1269177446

@whitslack:

> Consider the case where I am paying someone on chain under the stipulation that _they_ will eat the mining fee. (Thus, I specify _their_ address in `subtractfeefrom` when I'm constructing my transaction.) Later, they tell me that they can't wait for confirmation any longer and need an urgent fee bump. If I naïvely specify their output as the `reduce_output`, I may end up paying them _**much more**_ than I intended to if I only have large UTxOs in my wallet.


### Expected behaviour

Not sure.

Improving the docs is one option, but this behaviour seem quite counter intuitive.

My own suggestion:

> Should we disable the adding of new inputs when `reduce_output` is set? If someone really intends to do that, they should probably use `outputs`.

### Steps to reproduce

Haven't tried.

### Relevant log output

_No response_

### How did you obtain Bitcoin Core

Compiled from source

### What version of Bitcoin Core are you using?

Master after #26467

### Operating system and version

Any

### Machine specifications

_No response_
CMutableTransaction temp_mtx{*wtx.tx};
        for (auto& txin : temp_mtx.vin) {
            txin.scriptSig.clear();
            txin.scriptWitness.SetNull();
        }
        temp_mtx.vout = txouts;
        const int64_t maxTxSize{CalculateMaximumSignedTxSize(CTransaction(temp_mtx), &wallet, &new_coin_control).vsize};
        Result res = CheckFeeRate(wallet, temp_mtx, *new_coin_control.m_feerate, maxTxSize, old_fee, errors);
        if (res != Result::OK) {
            return res;
        }
    } else {
        
        new_coin_control.m_feerate = EstimateFeeRate(wallet, wtx, old_fee, new_coin_control);
    }
    
    
    
    
    
    
    
    for (const auto& inputs : wtx.tx->vin) {
        new_coin_control.Select(COutPoint(inputs.prevout));
    }
    new_coin_control.m_allow_other_inputs = true;
    
    new_coin_control.m_min_depth = 1;
    constexpr int RANDOM_CHANGE_POSITION = -1;
    auto res = CreateTransaction(wallet, recipients, RANDOM_CHANGE_POSITION, new_coin_control, false);