[muddy] the (waters|issue)

to complicate a simple situation

The idiom "muddy the waters" draws from the idea of stirring up sediment in a clear body of water, making it cloudy and unclear. It is used to create confusion or complicate a situation by introducing unclear, irrelevant, or distracting information, making it difficult to understand or reach a clear decision.

The conflicting testimonies from the witnesses muddied the waters of the court case, making it hard for the jury to determine the truth.
The addition of so many irrelevant details in the report muddied the issue, making it challenging to grasp the main points.
The heated argument between the politicians further muddied the waters of the already complex policy discussion.
John's attempt to bring up past issues during the team meeting only served to muddy the waters and distract from the current problem.
Rather than clarifying the situation, the supervisor's vague explanations only served to muddy the issue even more.