Hi Paz,
Both AdMob and Ad manager is an ad server where the SDK requests an ad. If you’re interested in running direct sold ads, indirect ads or house ads, Google Ad Manager gives you the sophisticated controls to deliver the right ads, to the right users, at the right time.
Since the Demand-Side Platform you are asking is more of related to Ad Manager, I would recommend contacting the the
Ad Manager Support team as they would be able to provide a better insight regarding to your concern.