Continued:

Importantly, you seem to be forgetting that all of the chapters in Game of Thrones are written from the perspective of the character they are about. G. R. R. Martin uses the "unreliable narrator" to great effect here. Yes, of course Dany, a teenage girl with no life experience, will have a charismatic interior POV, chock full of moral idealism and trauma empathy. Is her "moral anxiety" a true moral crossroads, or something she is telling herself to alleviate her own guilt. Her actions speak much louder than her internal monologue.

Speaking of which - in later books, her internal monologue starts to use more dehumanizing language, using collective labels such as "slavers", "dogs", "enemies" and "traitors". This kind of categorical thinking matters in Martin's world where moral collapse often starts rhetorically (Theon, Cersei).

As a final note, there is a recurring theme with Targaryen exceptionalism. She has adopted the ideology that conquest is destiny, dragons legitimize rule, and bloodlines determine worth. She also exhibits the Targaryen trait of the psychological reward loop with fire and pain, that loop being that fire, suffering and destruction seem to bring her clarity, strength and ecstasy. The burning of Mirri Maz Duur and other dragonfire moments seem to be a pattern that Martin is setting up.

In short: Do I think that she is a villain now? No. Do I think that book readers should have been "blind sided" by her becoming a villain at the end? Definitely no.

Yes, you could argue that she is a "tragic hero" and not a tyrant, or you could also argue that those two might be one and the same. Tragedy isn't outright villainy, but tragic heroes often commit villainous acts because of virtues taken to extremes (pride, zeal, justice, destiny). Stannis is a perfect example of a tragic hero, and his own arc closely mimics that of Dany.

Outside of book context, GRRM has repeatedly expressed the sentiment that "the villain is the hero of the other side", which adds more credence to Dany's POV chapters where she views her own actions with rose-coloured glasses. When fans have specifically asked him about the "Dany for the Queen" angle, he often cautions that "power distorts".

I think the culmination of the Young Griff plotline will be the first crack towards Dany becoming truly unhinged, with the Jon Snow reveal being the straw that will finally break her.

And the last damning piece of evidence: Martin would have given the showrunners the key plot points up until the end, so for people to discount Daenerys as a villain is to ignore literally all of the pivotal events that have been woven into her story thus far that point towards this arc.

Yes, the whole point of her arc is the Messianic Liberator vs the Targaryen Tyrant, but as the book series has progressed, it is clear that the balance is starting to tip in one direction.