Remove apps from my watch

Press the Digital Crown on your Apple Watch to bring up the App View.

If you're using List View, swipe left across the app you want to remove, then tap the red trash button. If you're using Grid View, tap and hold to activate jiggle mode, then tap the X in the top-left corner of the app you want to remove.

Tap Delete App to confirm.

Not all apps are available to delete.

Or this;

Unpair your Apple Watch via the Watch app on your iPhone.

Then Re-pair your Apple Watch again,this usually frees up

enough storage space to update your watch.And without any loss of data.