Hi @Ruben Magalhães, sorry that I missed this question.
You probably already found another way around that ever since you posted this question. If you did, would you mind sharing the solution that you found?
As for your question, I would first consider trying to find a way of not using Formula/Flee for this, since I believe that using this component for this use case might add too much complexity.
If your form inputs are completely dynamic, you could try parsing those variables onto a list and running a For Each on that list, checking if their values match the expected values, and setting a Boolean flag on the current record indicating that this particular form field should be highlighted on the UI.
Now, if you absolutely still want to use Formula/Flee for this, there are ways of doing this using the FormulaEvaluateText Action. One idea is to return a string with the field names that successfully matched your expected values as a CSV. See the following formula as an example:
If(Code_1 = "sometest", "Code_1", "") + "," +
If(Code_2 = "tbd", "Code_2", "") + "," +
If(Code_3 = "123", "Code_3", "")
With the resulting CSV, you should be able to use String_Split on it and create logic for highlighting the form inputs that were found in the CSV.

Again, I believe there are simpler ways of achieving this without using Formula/Flee, but anything is possible.