Answer by HolyBlackCat for How to turn off this function in VS CODE

You can disable the file name highlight with:

"workbench.editor.decorations.colors": false,

And the red 1 (number of errors) indicator with:

"workbench.editor.decorations.badges": false,

But this is purely aesthetical, and has nothing to do with the lag. I recommend replacing the stock C++ extension with Clangd, from my experience it works faster.