Unity does not see the IDE. What to do?

Question

IDE

Windows 10 Enterprise
Unity is the latest (and the 2018 version was the same). The essence of the problem is that no matter what IDE I try, none of them see the Unity syntax (highlight it in red).
And I tried the following:
Visual Studio (the plugin is worth it), Rider, Visual Code, Consulo (at first I saw it, but after a while I also stopped)
Errors in these editors do not give any specific recommendations (they just write about unknown syntax and the MonoBehavior class) .
What to do? Is there any way to solve the problem without reinstalling Windows? Maybe install (reinstall) something?