Disabling Incoming Call Notifications from Instagram/Snapchat on iPhone

I would like to disable incoming call notifications from apps like Instagram and Snapchat on my iPhone. Even though I’ve already turned off all notifications for these apps via Settings > Notifications, the calls from these apps still appear on my screen like regular phone calls, which is very disturbing.

Is there any way to completely block or silence VoIP call alerts from third-party apps like Instagram and Snapchat, so they don’t show up on the lock screen or interrupt what I’m doing?