Roll-on epoxy over self leveling concrete
I saw on another thread that someone said to use a concrete resurfacer. Which means it isn't self levelling. So the work to get it flat will be about 3000 more calories than your self levelling idea. But from what i know about floors you have to wait 20 days after pouring concrete before putting the epoxy down. Because of moisture evaporation and the drying process. Good luck.