re: Any major differences between Kindle tablets?

Check the USB port on them. The microUSB ports on the kindles tend to shite the bed. I went with the 8 plus for my kids since they use usb-c as well as wireless charging. My oldest had a fire 10 but the screen cracked just taking the case on and off (case has to be removed for Osmo apps). Also think about storage capacity since it isn't expandable.

Just a thought.

Edit: Also look into the trade-in program. You wont get much for the broken tablet BUT sometimes you can get a hefty coupon for the new kindle.