If in Visual Studio I just change "Output path", VS will always add target framework to folder structure, like "netcoreapp3.1" ("C:\projects\EFCore\tools\netcoreapp3.1"), in order to avoid this, right click on the project, click on "Edit Project File" and add:
<AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
From here