Update: Same number and same time!
Dear, my name is Miguel, I previously made a video on how to install WhatsApp natively on the Samsung Galaxy Watch 4 (INSTALL:
NOW IT WORKS !!!! You have to install the Google Contacts APP, synchronize them and open WhatsApp from the contact you want to call or send a message to.
HOW TO USE WHATSAPP: https://youtu.be/_Kpm3zL4pns
WHATSAPP GROUP CALL: https://youtu.be/iGmv3Oq61B8
Once WhatsApp is installed, you need to install the "Google Contacts" app, then do a sync.
And from the Google Contacts App you can use WhatsApp.
Unfortunately if you want to open WhatsApp directly it closes.
That is why the need to Install the Google Contacts App.
Link Video Tutorial: