My dad's Galaxy Note 20 vibrates twice BEFORE the ringtone begins sounding on incoming calls. He misses many calls because of the delayed ringtone. We have disabled "vibrate while ringing." It still vibrates, then rings without vibration. HELP!
If vibrate while ringing is Off @ACBoisson then that's how the phone should be acting on incoming calls.
Does this happen no matter which ringtone he chooses ?
Just to make sure no other app is conflicting with his phone app ask him to put the phone into Safe Mode.
Put the phone in Safe Mode which disables your downloaded app's but let's your stock app's keep working. If the issues stop then this highlights a downloaded app as the possible issue. Come out of Safe Mode and start deleting your most recent downloaded app's one at a time until it stops. https://www.samsung.com/uk/support/mobile-devices/how-to-start-my-galaxy-device-in-safe-mode/
If all else fails then ask him to consider backing up and factory reset.
Current Phone > Samsung Z Fold³ 5G.