i use an Xyron for work. I mainly use it for laminating, but you can make stickers and magnets with it. You can buy them off Amazon, just make sure you get the permanent adhesive cartridges, as the repositional cartridges aren’t very sticky. I have an A3 one, but I’d recommend the 510 model for a child, it’s big enough for turning credit card sized photos into stickers, and easy enough to get refills (expensive and difficult to get the size I need😬) It has much more scope than the ones you’ve listed, as well as turning photos into stickers or magnets you can either print off any image you want, or he can draw and colour his own design, or colour and cut out pictures from a colouring book. He can make book marks too!
He’ll need a bit of help initially, but once he’s got the hang of it, they are really easy and fun to use!