Go Raspi.
They've got a laptop already for playing Minecraft so use their love of the game to broaden their knowledge.
Minecraft Pi allows coding to be used with Python and they can interact and alter the Minecraft world via code. Once they are good at his, there are hundreds if not thousands of Python tutorials out there, such as "Python for kids".
You've used something they love to introduce something new, then they've got the tools to expand on that something new freely available online.
I can only see spending time on Minecraft to be a positive thing, it's how kids play these days, no one told me I was spending too much time playing with Lego when I was 6
Without being that parent, an hour a day for a 6 year old on Minecraft sounds like a lot of gaming screen time. How does the 8 year old manage that, plus school, plus homework?
Thanks for these, having a read.Shotcut is a great free video editing software, handbrake for compression and OBS for recording.