You can get the data off of this device and fully reset this iPad, but forget abut giving this old iPad to your granddaughter and just properly recycle this device.
If your old iPad model has been stuck on iOS 10 for all of these past years, then you own an 8-1/2-year old, 2012 iPad 4th generation.
That iPad model cannot ever upgrade beyond iOS 10.3.3/10.3.4.
Your nearly 9-year old, iPad 4th gen model is too old and obsolete, now.
Sorry.
Apple ended support for all 8-10-year old iOS devices well over 4 years, ago, in 2016.
Third party app developers abandoned and stopped supporting these 8-10-year old iOS devices nearly 3 years, ago, in 2018.
There are, virtually, NO MORE third party apps available from the iOS App Store, any longer!
Third party compatible apps for such old devices are few and far between, now, in 2021.
Your granddaughter will never get any third party compatible apps for that iPad model any longer.
Sorry & Best of Luck to You!