Well, Mannheim gets very specific. Ideology is psychological mystification, self-justificaiton at a more self-serving level. Which is why he moves to "Worldview" as the larger, overarching concept. Which brings the discussion to a different place.

Worldview has been reformulated into many derivatives, World Image. Life World. Etc. The basic idea is cognitive/metaphysical though, that our thought is predicated on a conception/image/model/picture/sense of THE WORLD that it cannot be separated from.

This was an important debate between Heidegger and Husserl for example. As Husserl wanted philosophy to be pure science. But Heidegger insisted, as many like Dilthey did, that Philosophy cannot describe the world apart from the framework of our worldview.

So every person has a worldview, and this is true throughout history. So a peasant had a worldview in the middle ages. etc. For Mannheim, his point is to draw attention to the way that theory/philosophy became self-conscious of worldview/ideology in the 19th century

This self-awareness breeds complications that undermine our ability to mitigate claims about reality. The theoretical awareness becomes the basis of "Ideological Critique," which was first and most devastatingly used by Marxism. But this then filtered into all of philosophy.

This becomes essentially a core problematic of modern philosophy and theory, as these issues must be resolved. How can we know that the way we approach the world is valid? ie how can we know that it is grounded in a "true" or "real" worldview that meaningfully relates to reality

Under Neoliberalism this entire problem has been sidestepped through information control systems, public opinion managements. Worldview has become a product. And it no longer functions as a basis for "life," or for us to harmonize ourselves with the world. But weaponizes us.