Exposition does have its place, however, it should not be relied upon.
Say for instance, you have a bunch of characters that live in a world that is unfamiliar to ours. You have to, as a writer, explain the rules for this universe to the reader in some way, so that the reader can enjoy the story more. So how would you tackle this problem?
If the characters have lived in this world all of their lives, it would be weird for them to explain the intricacies of how the world works through a casual conversation. It's like telling someone you just met, "oh yeah, there's gravity here on earth." So oftentimes, these kind of stories rely on a fish-out-of water character, someone who has lived their lives outside the system and then needs to be explained that system, that way a reader can latch onto the learning experience.
This type of story however is super common, and is still heavy on exposition. I would agree that telling the reader how they should perceive the world you made is important, but I lean towards explaining that through action and interactions, not through paragraphs of text.
To me, if you can't display your world (or at least a part of it) to the reader through an event or a single scene of natural dialogue, then your concept is either too complicated on its surface or just needs to be flat out explained for the rest of the story to be enjoyed.
As for heavy descriptions, those should be as minimal as possible in my opinion. You should be able to fill in the gaps with your own imagination while you read.