Sure, but this is perceived performance and it's 100% unrelated to the language. It's bugs, I/O, telemetry, updates, ads, other unnecessary background things, or just dumb design (e.g. showing onedrive locations first when trying to save a file in Word) in general.

C won't help with any of that. Unless the cost of development using it will scare away management which requests those dumb features. Fair enough then :)