Oh now reading it fully you’re so right.
The argument could be, if not for Princess Rhaeny’s children’s age being put to question she just as the conquerors if so desired could claim the throne through conquest.
The have the riders, the dragons, yet two lack the age, and skill as Rhaenys does.
Rhaenys if so chose to and succeeded to conquer the throne could make either child heir and still have a spare to make the Velaryon a new dragon house.
Yet Viserys is too stupid to see that, Corlys wants it, the only thing stopping it is Rhaenys.
Whether she fully realizes it or not. Maybe Daemon and Alicent too, along with other side characters.