Requisites

• Download Shelter - an open source app from F-droid or GitHub. Quoting the developer, use cases

• Run “Big Brother” apps inside the isolated profile so they cannot access your data outside the profile

  
  
  
  
  

  • “Freeze” (disable) background-heavy or seldom-used apps when you don’t need them. This is especially true if you use apps from Chinese companies like Baidu, Alibaba, Tencent.

  
  

  • Clone apps to use two accounts on one device

  
  

• Create a dummy gmail account to be populated with only Whatsapp contacts




• Device with work profiles (post Lollipop all have them) unless you used a Magisk or Xposed module to disable this

Methodology

1. Export your contacts to your dummy Gmail account. Follow instructions here or any other way, like this Export telegram and whatsapp contacts to vcf?
   . Delete all non Whatsapp contacts from this account (you don't want Whatsapp / Facebook to see ALL your contacts , right?)




2. Add this account to your phone from Settings → Google → Account ( will vary , but you can search)




3. Install Shelter




4. Click on the app to see two panes Main (where all your apps are listed) and Shelter where you will see contacts , Google Play Store. Go to Main and long press on Whatsapp and choose Clone to shelter (Work Profile)




5. Go to shelter tab and set up Whatsapp as if it is a new account and when it asks for contacts point it to the dummy Gmail account created having Whatsapp contacts




6. Delete all Whatsapp contacts from your main account and if you wish uninstall or Freeze or disable Whatsapp

Note: Open whatsapp from within the shelter (work profile) not from the app drawer. If you open from outside you will find Whatsapp having access to contacts and gallery. Once you install whatsapp it is completely limited to the storage dedicated to the work profile and cannot see storage outside the work profile

Profit Your contacts and photos are separated ! and Whatsapp will not see at least your future non whatsapp contacts / pictures

On a side note, even with root and mighty Xposed module like XprivacyLua , a successor to Xprivacy, contacts by group cannot be separated ; in other words you can only choose all / starred/ non starred contacts to be visible per app but you can't say hide my Whatsapp contacts ( For more details see Para 18)