Does user privacy when using WhatsApp Web (https://web.whatsapp.com) differ substantially from using WhatsApp on Android? WhatsApp on Android has end-to-end encryption and (optional) encrypted backups. If I use WhatsApp Web, will Meta be able to see the contents of my WhatsApp messages?
Meta still controls all the code running in the web app. They may be scraping your messages just like they have the option on Android.
It can still be end to end encrypted with them sending themselves a copy from the unencrypted text boxes you see