You have to analyze your own writing.
You are weaving together three things.
The Plot, the basic events that force characters to take actions. eventX happens, charA respond with eventY, leading to charB to respond with eventZ, and so on. The chain of "cause and effect", including failures, successes, eventually playing out as defeat or victory or some mix of both.
The Setting, which impedes or accelerates action in the story. If its medieval, travel may be slow. If magical, perhaps fast for a few. If civilized law may impede actions, if uncivilized (including futuristic outer space) perhaps its the law of the jungle.
Character development. Characters have personalities, likes, dislikes, multiple goals, and things at stake. Who they want to protect, what they are willing to suffer pain to keep, things wrong with them, weaknesses, strengths, loves and lusts.
The danger of overwriting something is boring the reader, communicating details that don't really matter to the story, OR the atmosphere, OR the character development.
To analyze your work, you need to identify why you are writing something, exactly what in a general sense are you trying to communicate to the reader?
For example, is it the beauty of nature in your imagined world? Fine, that's worth communicating. But it isn't worth communicating endlessly, it gets boring. Does the beauty of nature matter to the characters, or is it taken for granted because they have spent their whole life in it?
It does no good, and it is bad writing, to constantly hammer the reader with the same basic information over, and over, and over. There are only so many ways you can say Jack was overwhelmed by this beautiful thing, then that beautiful thing, then this other beautiful thing, before we think something is wrong with Jack.
That's the first principle, don't be endlessly repetitive; it is like somebody obsessed with sex that tries to inject sexual meaning into everything. Fun for the author, perhaps, but irritating to readers that aren't obsessed with sex. Try to identify your particular obsession so you can restrain it.
Imagination is certainly fine, but details in a setting have an exponentially declining value to the reader. Too much detail bogs them down, it is too much of a memory strain. If your imagination overflows, that's fine, just don't put it all on the page: Make a list of what you are imagining, stop for a few minutes and don't look at it, then without looking, list the most important three things. Don't overload the reader, descriptive prose of a scene (or machine or whatever) gets exhausting quickly.
You say you are a fan of something: Analyze the descriptive prose in THAT work, and see how much a scene is described just in raw words. (There are roughly 250-300 words per page in most books). Try to emulate that average, no more. If the description of the setting is broken by dialogue, character feelings or thoughts or character action, emulate that too. No uninterrupted descriptive prose longer than what you are already a fan of reading.
Prose is an interruption of the flow of action. You can get away with more at the beginning of chapters, or scene changes, because there is little going on with the characters at those points.
But once the characters are involved, readers are interested in character actions and interactions, feelings and thoughts. Readers are there to become the characters, imagine themselves as the good guys on a harrowing adventure. Settings are there to help or hinder the action, to echo the feelings of the characters, or contrast them, or to force the feelings of the character.
It is fine to over-imagine things, that's a valuable asset for a writer. But not to put every one of the twenty things you imagine on the page: Over-imagining lets you choose the best two or three things to put on the page. You need to be analytical about these things you have brainstormed, prioritize them, and pick the few most important or impactful or representative things. That way, you don't overload the readers memory or slow down the story too much. To choose, I'd focus on the characters and how the details can affect them, it is good for characters to notice the details that create some sort of emotional reaction, memory, or feeling in them. Anything from a fond memory to disgust, missing a friend to anger. Relate details to their past, and you get a two-for-one: Mental imagery of a scene and character building.