I know where my problem is coming from because every time I open vscode, a folder called 'net461' is automatically created at a location such as 'C:\Users\hjjls\AppData\Local\Temp\dotnet-script\E\netenv\bofu\Auth'. This is the root of a series of problems I am experiencing because I have not installed any versions other than .NET 7. Therefore, if the script in the .csx file secretly decides to use another version such as net461, then it will produce the series of errors I mentioned earlier. Is there any way to solve this problem? Currently, I can only manually delete it, and deleting net461 can solve the errors such as duplicate assemblies that I mentioned earlier.

by default omnisharp will treat your scripts as net461 which is hardly what you want - it seems you want to have net7.0.
you should create a file omnisharp.json at the root of your script folder with the following content

{
  "script": {
    "enableScriptNuGetReferences": true,
    "defaultTargetFramework": "net7.0"
  }
}

You can also do it globally by adding this omnisharp.json to the %USERPROFILE%/.omnisharp/ folder

by default omnisharp will treat your scripts as which is hardly what you want - it seems you want to have . you should create a file at the root of your script folder with the following contentnet461``net7.0``omnisharp.json

{
  "script": {
    "enableScriptNuGetReferences": true,
    "defaultTargetFramework": "net7.0"
  }
}

You can also do it globally by adding this to the folderomnisharp.json`` %USERPROFILE%/.omnisharp/

Ok thank you, my problem seems to be solved!