What phone or tablet setup suits a 6 year old?
For a 6 year old, keep it small. A few learning and play apps, no Play Store, adult sites blocked, calls to family only through a short list of numbers you control, and a bedtime lock. A tablet usually suits this age better than a phone.
At six, the aim is not independence. It is a safe place to play and learn. A tablet at home often does the job better than a phone, because there is nothing to carry to school and nobody to message.
With Skie you pick the apps your child gets, and everything else is hidden. A reading app, a drawing app, a maths game and the video app you trust is a fine list. Hide the Play Store so a six year old cannot download something while you are cooking, and nothing can be bought by accident.
Chrome, if you allow it, has SafeSearch forced, YouTube restricted mode on, and incognito blocked. Adult sites are blocked at the network level on the device, so it works on any Wi-Fi and on mobile data. For a child this age, you may prefer to leave the browser off.
Use schedules. A window for after school, another for the weekend morning, and a night mode that leaves nothing but the clock. The device locks itself on time, so you are not the one saying stop each evening.
Contacts-only calling is not available yet. If the device is a phone, outgoing calls can be switched off or left on. Per-app time limits are not available yet either, so use windows. Pricing for Skie is on request, and it works on the tablet you already own once it has been freshly set up or reset.