Getting a negative review removed isn't always easy, but it is often possible...

https://wiki-zine.win/index.php/Report_vs._Removal_Request:_Navigating_the_Google_Review_Landscape

Getting a negative review removed isn't always easy, but it is often possible if you know the rules. Google will take down feedback that clearly violates their policies, such as spam, conflicts of interest, or irrelevant content