This is going to be a bit of a rant on my part, as I’ve seen this trend in multiple books and circles in regards to Sovereignty Goddesses and disempowering them. My area of interest is with The Mórrígan, of course, but I have seen this with other deities as well.
It drives me up a wall to see folks removing the agency from these deities, reducing them to a “handing off” of power to someone (usually men in the lore) and that being all they are good for. Generally in the Irish lore this is seen as the goddess having sex with said person, or in a ritual marriage to the person, thus cementing the king’s tie to the land and its people. This was generally how kings were accepted into their position, and people seem to leave these goddesses behind in their mind after the coronation.
Sovereignty is FAR more than kingship, and it is certainly not the goddess handing over all her power to these kings. By choosing these people to be sovereigns, the goddess is showing that these people can do what is best for the land and its people. These people are capable of carrying out HER wishes, doing HER work, carrying out HER will. Sovereignty is not about getting power, wealth, recognition. Being a sovereign is about stewardship and right relationship in the highest sense – you are doing the Work for the people and the land. Either you do the job you were chosen to do or you get tossed in a bog somewhere and try again next life.
The TL;DR being this: The gods are not sex toys to give you power and glory. If you are chosen by them you are here to do what they want, not the other way around.