Once she has finished her relationship, a spoiled young girl begins an exhaustive walk inside of a psychedelic, exclusive and private universe fighting for free herself from pain against the current of her misconceptions about how the love works.
A protagonist with emotional problems, with a profound subjective need, is excellent raw material for a drama.
But “an exhaustive walk inside a psychedelic, exclusive and private universe” refers to an intangible, internal conflict. The problem with that is that film is a visual medium. All conflict, no matter what it is, must be visible.
A logline is a brief description of a movie plot. And a plot is about a protagonist struggling to achieve an objective goal, that is, something that can be seen. Somehow “the exhaustive walk” must be externalized, portrayed right out there on the screen for the audience to see.
So the trick to building a film plot and a logline with the raw material of your young woman’s emotional conflict is to have an inciting incident that places her in a specific dramatic situation that forces her to overcome her subjective problem in order to achieve her objective goal.
As an example take the 2010 movie “It’s Kind of a Funny Story”. When a suicidal teen (troubled protagonist) checks himself in for an overnight stay in a psyche ward (inciting incident) only to discover he can’t leave for 5 days (dramatic problem), he must find a way to escape (objective goal). The plot of the movie explores his subjective conflict within the context of the psyche ward in which he has unwittingly become trapped. His struggle to escape (his objective goal) becomes the means by which he solves his problem.
So I suggest that is what your logline needs to do: throw your troubled protagonist into a specific situation that compels her to struggle for a specific external objective goal that she can only achieve by overcoming her psychological problem (aka: her character arc).
So, in effect, her struggle for the objective goal unwittingly becomes her therapy, the way she heals herself.
As another example, consider “Ordinary People” (1980), a profoundly moving and psychologically insightful film about a protagonist fighting against depression and guilt, against the overwhelming urge to kill himself. (It “only” won Oscars for Best Picture, Best Script adapted from another medium, Best Actor and Best Director.)
In “Ordinary People” the accidental death of a brother in a boating accident plunges the surviving brother into a suicidal spiral of grief and guilt. That is the cause of his psychological scars. The movie opens with a PTSD flashback to the incident, the boating accident, that triggers his crisis.
In contrast to specificity of “Ordinary People”, the inciting incident of your logline is vague. We have no idea how or why she “finished her relationship”, no clue as to HOW she is suffering so much as a consequence. We don’t know what makes her suffering different from anyone else’s suffering in any other film about a character dealing with the breakup of a romantic relationship.
So: what is the specific event that ends the relationship, plunges her into her emotional crisis?
And as a result of that event, what MUST she do about it? What becomes her specific objective goal, her specific plan to heal those scars?
And here’s a big one: what’s at stake if she fails? (In “Ordinary People” the stakes are the protagonist’s very life — he’ll try to commit suicide again.)
I hope this helps.