Yes, that is how WhatsApp handles storage. Here is your other post:
WhatsApp storage discrepancy on 64 GB iPh… - Apple Community
You can review WhatsApp support. They know there is a discrepancy, but have not offered a better tool to evaluate device storage from their app:
It's possible that there might be a difference in the storage usage noted by your WhatsApp app and iPhone. This is mainly because of the difference in the way WhatsApp calculates storage versus your iPhone.
https://faq.whatsapp.com/5503646096388294/?cms_platform=iphone&helpref=platform_switcher
If you truly want to clear your WhatsApp storage, you can delete the app with all of its storage and download it again. If you want data backed up, you should check further with WhatsApp help.