Indeed there is not an official whatsapp for The Watch Active, however it is possible to receive notifications by pairing . See more here https://www.samsung.com/uk/support/mobile-devices/how-to-activate-whatsapp-notifications-on-a-galaxy... https://www.tizenhelp.com/how-to-use-whatsapp-on-samsung-smartwatch/
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
My Device- S21 Ultra 5G ( SM-998B/DS ) CSC= BTU , 12GB/256GB
One Ui 4.0,Android 12 Official Version.