Something is very wrong with your system configuration if VS Code has issues showing keystrokes in realtime. It's not a VS Code or electron problem.
Haven't had this problem with other text editors.
It's imperceptible to some. Not to me. Drives me up the wall, but the vscode integrations are too good.
(In my particular case I've a passively cooled laptop from like 2021; The limited compute resource available to applications in that device really made me appreciate the well built applications)
Of course you can always go less powerful but at one point you just can't use all more complex editors. It's not an electron issue.