(Simons game) How to avoid multiple clicks in less than a second on a button?

Hi everyone. I have an issue with my last project in javascript. A Simon game that you have to follow the sequence of the button (4 buttons).

The bug I am facing is that, the code runs normal, however, when/if I click multiple times on one of the four buttons or even the start one the code crashes, making all the events trigger themselves without a click.

I have added async inside of the event listener method but with no success. Sorry to disturb, I am not so good at JS since I am backend dev. If you could give me a help I would appreciate.

Here is the code:

you can see the event listerners buttons as commented

Here is the game url: