I work for/with/teach pro colorists, who of course master a fair number of DCPs.
Typically a 'master' file is created, either ProRes or a DNx variant, and then a DCP is also created. The DCP is often H.264. BUT ... various festivals may have entirely different spec sheets. So knowing which festival, and getting their specific spec sheet, may be required.
And note, some spec sheets are written by people who don't actually understand the tech details. Which is frustrating when they 'demand' something that isn't possible. Plus ... actual theatre specs tend to be done with a 2.6 gamma grading display transform on the colorist's screen, and to a 48 nit max brightness. And a particular white point also.
So ... it may be you need Rec.709 graded on a gamma 2.4 display in that semi=darkened room, or graded at display transform of 2.6 in a totally darkened room to a P3 spec. Who knows, until you get The Sheet.