IF it is set on the watch and within the gear app notifications, should work, best try restarting both if you haven't already.
Oh if it is checked, uncheck and recheck WhatsApp.
Regards, Obsydian
DAILY DEVICES
ZFold4 [Mobile], Pro5 [Watch], S8 Ultra [Tablet], Book2 Pro i5 5G [Laptop], Buds Pro2 [Buds] M70A 32/43" [Monitor], Smart Tags+, iPad Mini 5 and iPad Pro 12.9 GEN2 [Tablets], Dell Inspiron G5 Laptop
HOUSEHOLD DEVICES
ZFlip3 and ZFlip4 [Mobile], Watch5 40mm and 46mm [Watch], S7+ and S6 Lite [Tablet], QN95A [TV], Q900A [Soundbar], MC28M6075 and MC32K7055 [Microwave], Jet 75 Complete (Vaccum), Samsung Level [Speaker], Buds Pro [Buds], iPhone 12, iPad Air 2, Air tags