Unity 2018/2019 intellisense not working annywhere

Intellisense is recently not working anymore(it used to work).
I have tried it in unity version 2018(multiple versions) and unity 2019.
Also, I have tried it with multiple software including visual studio 2017, visual studio code and MonoDevelop. but in none of them, I could get intellisense working even with all the packages installed.

I’ve finally found out what the problem was, and it turned out I needed to downgrade .NET back to dev 4.7.1

Try Edit → preferences → external tools → external script editor = Vs 2019.

Now if your issue is only with the function descriptions now showing then we are in the same boat, i made a post on the forum , I will update this if i get an answer.