Beginning at 18th level, you can channel the dread presence of your Dragon ancestor, causing those around you to become awestruck or Frightened. As an action, you can spend 5 Sorcery Points to draw on this power and exude an aura of awe or fear (your choice) to a distance of 60 feet. For 1 minute or until you lose your Concentration (as if you were casting a Concentration spell), each Hostile creature that starts its turn in this aura must succeed on a Wisdom saving throw or be Charmed (if you chose awe) or Frightened (if you chose fear) until the aura ends. A creature that succeeds on this saving throw is immune to your aura for 24 hours.
Per the rules established in regards to the Draconic Presence ability, any creature that fails a Wisdom saving throw while starting their turn in the DBS's aura is either Charmed or Frightened. There is no saving throw after the initial saving throw and therefore, the 1 minute of being Charmed or Frightened is mandatory (I'm also presuming that this aura lasts for a turn, and isn't active for the rest of the session).
While in the case of a creature being Frightened, there is a chance of breaking from the aura by attacking the DBS and breaking concentration, Charmed has the following effect:
A charmed creature can’t Attack the charmer or target the charmer with harmful Abilities or magical Effects.
As the Charmed creature cannot attack the DBS, would it be a theoretically viable strategy for the DBS to use Draconic Presence to Charm a single opponent and then keep making attacks and spells until the 1 minute ends, fully knowing that the Charmed creature will never be able to attack the DBS?