Can you extract files from a Google Drive Whatsapp backup? I have accidentally deleted hundreds of pictures from my Whatsapp files in my phone, but I can't restore the backup, since Whatsapp is a system app and I can't uninstall it.
Answering your main question - no, you can't.
As for having Whatsapp in a phone firmware, I think reseting an app through deleting its data in Android settings could do the trick, but it may also delete local backup files - so "backup the backups" first (sdcard/WhatsApp/Databases).
Sources:
https://support.google.com/drive/answer/6305834?co=GENIE.Platform%3DAndroid&amp;hl=en
https://faq.whatsapp.com/en/android/20887921