So for two days now I have been trying to code but I no longer have intellisense or autocomplete in VsCode, visual studio is way too slow for my laptop, I installed the plugin for intellisense but nothing changed. Is this a flax bug or vsCode?
OK, so I think I’ve finally found a solution. Whenever I create a new script or change the script project in Flax, Visual Studio has to convert the .NET Framework from 4.5 to 4.8. This process is automatic. But in VSCode, we have to do this manually.
In your Game.csproj file, on line 12, you should find the <TargetFrameworkVersion>. Change that to 4.8.
Let me know if this works, please. 
Side note: I believe that the .NET Framework 4.8 will be in Flax 1.4, so we will not have to do this anymore after that.