How to get time and date not from the phone

Question

In android studio kotlin or firebase how do I get the utc time and date that will be same on everyone's phone.

This is the code for getting utc time:

fun getUtcTimeAndDate(): String {
    val df = SimpleDateFormat("MMM dd, h:mm a")

    df.timeZone = TimeZone.getTimeZone("UTC")
    return df.format(Date())
}

It gets the utc time from your phone but some phones have slightly different utc times.

I want to get the utc time from somewhere that on everyone's phone will be the same.