How to best "drop in" on grandma

I bought my elderly grandma an Echo 8 so I could drop in on her from abroad. I made her an own account with a new email address. Then I just logged into "her" account on my Alexa App, added her Echo, added my phone number, and now "drop in" to her Echo from the app.

However, I now accidentally seem to have deleted her device (and can no longer add it from abroad - right?).

But I'm generally wondering if there's a better way to do this. A way that lets not only me, but also other family members with Echos or the Alexa app (using their own accounts) drop in on her. I've always found it a bit confusing how the devices and accounts and phone numbers link.

I do have a relative living with her who will come to see me soon, and I do plan on getting an actual Echo device myself.