There doesn't seem to be much female Targs around at the same time as Dunk. I've found Aelora, Daenora, Daella and Rhae. They all seem to be younger than Dunk as well. So it would be the older lowborn omega/younger highborn alpha dynamic for all of them.

Aelora, from what I gather would share him with her twin brotherhusband, Aelor. I don't really know their ages but I'm imagining them as old enough to pursue Dunk together. Which is fun, that would fluster Dunk alot, I imagine. He can barely handle one highborn coming after him, two would send him over the edge.

Then there's Daenora, and the only thing that I know about her is that she married her cousin Aerion (gods help her) and was willing to name her son Maegor, I am assuming that was her decision as well. Someone willing to name their baby Maegor is definitely assertive in my head and she would not take Dunk avoiding her because she's highborn very well. She's the type to atticwife Dunk. (I am basing this off vibes)

Daella is Egg's older sister (by a year) and I just think of her having a sort of pup crush on Dunk that she wouldn't outright pursue. Idk, I'm getting shy vibes from the voices in my head. There's nothing backing this. I just think that she would be very hesitant to pursue Dunk, understanding the implications and not wanting to force him into anything but unsure whether she would stay silent if anyone else pursued him, possibly and then it would turn into an affair on the side because one day she just can't take it and Dunk is just one omega. How is he supposed to resist?

Then there's Rhae, who is younger than Egg by a year. Apparently she asked for a love potion to make him fall in love with her so they can marry and I just think that that's someone who knows what they want and would do whatever it takes to get Dunk in her bed and pupped by the end of the night that they first meet. She's putting a love potion in his drink and not thinking about the implications when it works because she's the one with the pretty tall omega now soeveryone can fuck off.

In general terms, just to cover all bases, Duncan with an alpha Targaryen princess would be so flustered. He would want to show off how good of a knight he could be to protect a maiden and they would find it cute that the omega wants to be such a chivalrous knight to them even though most female alphas aren't treated like "fair maidens" once they've already had their ruts. They would say that and Dunk would flush and apologize, shrinking into himself before they explain that they don't mind. I think that they could get away with naming him their sworn protector. Egg would be annoyed because he found Dunk and that's his mama now, please leave him alone. Idk, all this talk about omega Dunk just makes me think of Egg seeing him as his mama and everyone needs to back off right now or he's gonna start throwing wildfire at people.