To professionally say "over the top" you can use terms that highlight excess or unnecessary effort.
Good ways to say "over the top" professionally are to use the words "extravagant" "disproportionate" "exaggerated" or "excessive".
If you want constructive feedback for saying "over the top" you can use words or phrases such as "needs more focus", "could be more refined", or "can be streamlined".
These phrases and words can indicate that an action or a project went beyond the necessary limits.
Over engineered is also another way to say something is "over the top" professionally.
Over engineered could be used in a sentence, like "The solution may be slightly over engineered for this problem."
Or overextended, like for example, "The proposal feels somewhat overextended."
A professional way of using disproportionate in a sentence would be "The effort involved seems disproportionate to the result."
For excessive you could say "The detail that was provided is a bit excessive".
For extravagant, you could say "That approach is a bit extravagant for our budget."
Or you could use the word Lavish, for example, "That presentation was quite lavish".
Or over the top acting and effort, "The approach was quite extensive/dramatic."
Some constructive ways to say "over the top" for feedback include.
"We sure could streamlined this to be more efficient."
"Why don't we refine this to focus on the key objectives."
Or "This may be too detailed for the current cope."