DNAse for pre-wash, oxygen bleach for main a good strat vs combining them?

Not sure why I called it strat. But basically I'm having trouble finding something with both DNAse and oxygen bleach. Is it a good idea to have them in that order? and if so, will the DNAse have enough time to do its thing in the pre-wash cycle? Or is combining them is the better option? My DNAse detergent is liquid and my oxygen bleach is powder