"Optimal" based on what criteria? Most moral philosophy that calls itself that (rather than theology) neither assumes the existence of God nor inherent purpose in the universe, however, it does (necessarily) start from some moral axioms (without ascribing them as purposes of the existence of the universe).
Morality doesn't require the universe have a purpose, but morality has to have a purpose.
The assumption I made is that our knowledge can never be perfect, thus it's unknown whether there is a purpose or God in our universe and thus we have to continuously improve our knowledge just in case that there is indeed a purpose or God (even though it doesn't look like it).
Morality doesn't require the universe have a purpose, but morality has to have a purpose.