Is it okay to do a dark load after I bleach my white load, or will there be bleach still in the machine that can damage the darks?
It should be OK to do the darks after you have completed the bleached white load. I’m curious why you are concerned — it’s as if something has happened in the past to give you concern about this approach. And I’m not sure what you meant by “…the bleach is still in the machine.” After the rinse and spin cycles of the bleach load, all the bleach should have entered and been used up.
If you are still concerned, I might suggest that you stage your loads by doing whites, then lights and finally darks. This should alleviate any concerns about bleach carryover.