안녕하세요 강의와는 관련 없을수도 있는 질문입니다.

혹시 IDE로 vscode를 사용중이시라면 이 방법을 시도해 보시길 추천드립니다. I found a fix for this in VSCode and it's only a few steps. Your environment in VSCode may vary, but I have all the extensions you have in the OP. But here's what I experience. I make a new project, after OmniSharp loads in VSCode. The packages don't highlight correctly, and I don't have intellisense. So I do the following: Delete the Assembly-CSharp.csproj from the project. Go to Unity -> Edit -> Preferences -> External Tools Look for the section near the top called "Generate .csproj files for:" and click "Regenerate Project Files" with everything unchecked. Then in VSCode I press "Ctrl + Shift + P" and run the action for "Developer: Reload Window" Intellisense and all your other syntax highlighting should start working again. I hope this works for y'all. I am on Unity 2019.3.13f1