British English has several phrases that treat doing too much as a fault.
To gild the lily: To add decoration to something that is already fine. The phrase is a misquotation of Shakespeare’s King John, where the line is “To gild refined gold, to paint the lily.”
To over-egg the pudding: To do more than is necessary, or to exaggerate.
To use a sledgehammer to crack a nut: To use far more force or expense than a small problem needs.
Overkill: Much more of something than is needed.