You can disable inline suggestions from IntelliCode:

1. Go to File > Preferences > Settings.
2. Search for IntelliCode and find the settings labeled Editor: Inline Suggestions.
3. Uncheck Editor:Inline Suggestions to disable it.

Some C# extensions, like the C# Dev Kit, might also have settings for IntelliSense or AI-based suggestions

1. Go to Settings and search for C# Dev Kit or just C#.
2. Look for any settings that control IntelliSense or AI-based suggestions, and adjust them as needed.