My guess for the finale, FWIW:

Daenerys is in firm control now. The most likely path I see for her near term removal is assassination via poison, betrayal, or subterfuge; but she now wary and trusts no one - especially if she is aware of Arya's special gift. Indeed, one of her first acts should be killing Jon and Arya. Daenerys said herself she must rule by fear.

Another scenario, although remote, is Daenerys - horrified by her action - express remorse and returns to her true home to the East and lets Westeros' rulers (what is left of them) sort out governance.

It will be interesting to see if the writers find a logical ending that does not cheat the audience.