repair or replace windows11 operating system

I have a legit windows11 OS on my computer but it ran very slow. In trying to speed it up I have ended (or removed some critical files). For example, I deleted the WinZip capability and also my sound driver and other needed capabilities. To get windows11 working properly again (although slow) is it best to do some kind of repair or is it/can I download (reinstall) the ISO file from Microsoft? If I reinstall, do I need to delete anything before I reinstall?

Pete