In addition to being able to keep one of the Pokemon you capture during a Dynamax Adventure, players will also earn rewards for participating in these adventures. After each and every Dynamax Adventure, players will receive what is called Dynite Ore based up achieving certain goals. You will receive four Dynite Ore for Investigating The Pokemon Den, two for reaching the Legendary Boss Pokemon, three for catching the Legendary Boss Pokemon, two for completing a Dynamax Adventure without a Pokemon fainting, and two for participating with others online. Players can send this Dynite Ore at the Dynamax Adventure Shop.
In that same sense, there are also penalties for not completing Dynamax Adventures you begin. If you disconnect from Dynamax Adventures three times in a row, the scientist that runs them will not let you participate in another one until you have paid the penalty of three Dynite Ore. The penalty fee will even increase the more you do this.
We have questions and answers related to this topic which may also help you: