Is there anything solid in the lore or everything is based on point of view and religious beliefs?

Solid like what? What is it you're asking?

The Aedra take a largely hands off approach to things, so their influence isn't typically as, lets say directly felt as the Daedric Princes, if that's what you're after.

Truth. If what is written in the books are true.

Nevermind. Misunderstood the question.

"Each reader sees different reflections through different lenses, and may come away with a very different reading. But at the same time, all of it is true. Even the falsehoods. Especially the falsehoods."

Beyond that, good luck finding any morsel of "truth" in anything in this series. That said, given that we've actively partook in divine shenanigans on a regular basis up to and including stabbing the heart of a "dead" creator god repeatedly...yeah.