A user reported to me that they are unable to create a PSBT with a legacy watchonly wallet when they use the GUI. They get an error "The amount exceeds your balance".

I think the issue is that the GUI will retrieve the wallet's balance via `AvailableCoins` before calling `CreateTransaction`. This call to `AvailableCoins` is resulting in fewer coins being returned with recent changes to how `AvailableCoins` works, particularly with additional filtering of spendable coins and preset coins.

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Note that this does not effect descriptor wallets. A workaround for this issue is to switch to using descriptor wallets. An existing legacy wallet can be turned into a descriptor wallet using the `migratewallet` RPC. However many watchonly legacy wallets are likely the result of importing descriptors via `importmulti`. For such wallets, I recommend creating a new descriptor wallet and re-importing the descriptors.
{
    AssertLockHeld(wallet.cs_wallet);
    std::map<CTxDestination, std::vector<COutput>> result;
    CCoinControl coin_control;
    
    coin_control.fAllowWatchOnly = wallet.GetLegacyScriptPubKeyMan() && wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
    CoinFilterParams coins_params;
    coins_params.only_spendable = false;
    coins_params.skip_locked = false;
    for (const COutput& coin : AvailableCoins(wallet, &coin_control, std::nullopt, coins_params).All()) {
        CTxDestination address;
        if ((coin.spendable || (wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) && coin.solvable)) &&
            ExtractDestination(FindNonChangeParentOutput(wallet, coin.outpoint).scriptPubKey, address)) {
            result[address].emplace_back(coin);
        }
    }
    return result;
}
FilteredOutputGroups GroupOutputs(const CWallet& wallet,