Hi Archie,
I think your best course of action is to go to your app settings on your computer to delete whatever you don't want.
- Press your windows key.
- Search for settings.
- Navigate to Apps
From there you can go to your installed apps and delete whatever you don't need/want like your WhatsApp. Turning off your auto updates like you said you did from the windows store should prevent them from redownloading.
If you're concerned about unused apps taking up space on your computer and limiting your internet speed you can also check your advanced app settings (underneath installed app settings) and make sure you have archive apps enabled.