This is a very annoying issue. Once a person’s name is entered in google contacts, it should update Whatsapp contacts immediately. It doesn’t.

THESE OPTIONS DON’T WORK

OPTION 1: SYNCHRONISE CONTACTS

Phone’s Settings  > Accounts > WhatsApp.

Tap WhatsApp again  and resync.

OPTION 2: NEW CHAT

Open WhatsApp and go to the Chats tab.

Tap on the new chat icon.

If you can’t see your contacts, make sure that your contacts are using WhatsApp.

Make sure that you have saved your contacts’ phone numbers in your phone’s address book. If they use a foreign phone number, use the full international format.

Make sure you have allowed WhatsApp to access your phone’s contacts in your phone’s Settings app.

In your phone’s address book, make sure that all accounts and groups are set to “visible” or “viewable”.

THE BEST WAY IS TO CREATE A NEW WHATSAPP CONTACT

Even though this is very annoying and leads to massive duplication, this is the only way this works.

Some research notes:

The bunnings video.

but I like this one.

and this. THIS.

Here’s how: https://www.androidauthority.com/set-own-music-mp3-custom-notification-ringtone-166052/