What is the MSC timezone on the client? Or how to catch a click on now in the datetime picker?

Question

Vue.js

Vue 3 + Element Plus.
There is a datetime picker in the post creation form. Users will work with MSC time, even if they are not in this time zone. But on a click on the "now" button, it substitutes the local time.
I made a time conversion through @change so that by clicking on "now" there was the required MSC time. But then, after an arbitrary choice of time, it is also converted to MSC, that is, for example, I chose 17:00, and received (-4) 13:00.
I don't see anything in the docs about the "now" button. I think at least turn it off and make a shortcut for the current time. But ideally, it is to do your processing by clicking on "now".
Naturally, there is no button itself when using the component, there is no slot either.