Just to make you aware though - Monzo doesn’t yet offer direct debit or standing order retries (like you are probably used to with your traditional bank, where you have until 4PM to add enough money to your account to cover any direct debits).
Instead, they will let you know 1 day in advance if you don’t have enough money for any outgoing payments scheduled to leave your account the following day.
So if you don’t have the needed funds in your account at midnight on that day, they will be declined immediately, unless you have an overdraft in place.
However, Monzo won’t charge you an unpaid transaction fee.