Samsung tablet. You can get durable cases and set up parental controls. That way your kid doesn’t outgrow it so fast. The kids tablets you can’t do much on. Especially school work.
I purchased tablets for all my kids and realized it’s better that my kids don’t have tablets… I will allow them to use a Chrome book for Netflix Disney plus or streaming networks, but not kids youtube! I honestly suggest saving your money take the kids somewhere to do something fun instead of a tablet… Personally Samsung Verizon tablets are the best I’ve ever owned… however no table is better for the kids! 
Bought my 3 1/2 yr old the Amazon fire it had the best warranty & with prime deal days it was $60.
Give up the tablet for books!!!
Joy Tab 2! It can be financed from T-Mobile.
Mine had a galaxy tab a and I downloaded family link on it. You can set time limits, age restrictions and bedtimes so they can’t use past a certain time and then it unlocks on its own at the time you set. You can also block apps and set it to where they have to have permission to download anything or buy anything.
Can’t you set parental controls on your IPad?
Also, you can remove content off of it you feel aren’t appropriate.
You could also have him use Kiddle as a search engine, rather than using/having goggle.
Have you tried the APP ABC Mouse for fun learning?
We have the Amazon Fire for my 2yo and it’s set for her age. That way long road trips she has movies and books etc.
I like the Amazon ones
My older 2 (6 and 4) have the fire and we just got the youngest 2 both 2 years old the Samsung Galaxy Tab A (2019) 8 " 32 GB and they are great. The older kids would rather have the Galaxy’s. They said they are so much easier to use and get around.
We have the 10 inch Amazon fire tablet for our children and they love it and not broken them yet thank goodness for child case and screen protector 
When my then 11 year old had a fire tablet he easily hacked it:peach:
I bought him cheap Samsung that wasn’t as hackable
I have an amazon kids fire. Comes preloaded.
We have 2 of these…one for each of our toddlers and they are great and hold up amazingly to rough kids
My son is 2 & had the Amazon fire kids & loves it
I’ve used those kids specific tablets before and I honestly prefer the iPad over them. The iPad has much more space and durability, and does have parental controls on them where you can limit the apps, put time limits on certain apps, and a time limit on the whole thing. I wouldn’t waste money on those kids tablets, they are cheap for a reason.
My kids have a Samsung Galaxy tablet, 3 plus years and no issues. I’ve heard good things about the Amazon fire tablets too.