Can we make google duo video call using email on button click?

Question

I'm setting up an app that can make a video call. But, we're in hurry. so we just want intent to google duo.

I've been search how to make video call using google duo. But, we don't want to save user's phone number in our app.

Here's what I've found on internet.

val I = Intent("com.google.android.apps.tachyon.action.CALL")
i.'package' = "com.google.android.apps.tachyon"
i.data = Uri.parse("tel: $phone") // phone is the phone number your to a function
i.putExtra(com.google.android.apps.tachyon.extra.IS_AUDIO_ONLY, false)
startActivity(i)

That snippet is trying to make google duo video call using phone number. Can we just use user gmail?