There is one way, but after using it, vs code will report that its installation is broken, but this notification can be disabled forever. If that doesn't bother you, then:
- Go to the vs code installation folder;
- next, resources\app\out\vs\workbench;
- open workbench.desktop.main.css;
- Find the class.window-appicon
- change width:35px; to width:0px;
A source:https://www.reddit.com/r/vscode/comments/g4hyz5/how_do_i_remove_the_upperleft_corner_visual/