- Currently Glide does not have push notifications but there are plenty of workarounds for that in the forums. One of the options is shown in link below.
- No but you could always create a separate sheet for users to bulk add and use importrange to import the data in your app sheet.
- You can use a button (or a link component) and link it to whatsapp business API to have a WhatsApp option.
For WhatsApp notifications check out: Notifications