Something like this may be useful for very old people, or in other words, you may want to search also for phones designed for old people.

The iPhone has a mode called Assistive Access. It’s meant for older people or those with cognitive impairments, but could work well for children as well. It changes the UI, limits the apps available, and simplifies those apps, so they just have very basic features.

You could set it up on a cheaper or hand-me-down iPhone (if you have one).

https://support.apple.com/guide/assistive-access-iphone/welc...

My nephew had a Gabb watch for a bit. Would not recommend.

+1 for people who want no spying modules and need the phone to serve connectivity (tethering, hotspot).

I was very upset to find FB and similar on recent Nokia products.

Why not a Volte feature phone?

What ages?

For the phone, a good candidate is the Commodore Callback. Runs Linux, deliberately blocks all social media, operates like a semi-dumb phone.