If your addiction to distraction is comparable to that to cigarettes all bets are off, buying some overpriced gizmo will not help here since you'll just sneak off with your phone or tablet or laptop to get your fix. The solution to this problem does not lie with technology, it lies with behavioral changes. Technology can help, sure, but buying yet another device just for this purpose does not - it runs against the same problem as you pointed out around cigarettes: "just don't touch your phone/laptop/tablet/desktop/fridge door/'smart' TV/in car entertainment system/whatever other device you have around which can be used to browse the web. If you
really can not refrain from grabbing those things I'd suggest moving to the backwoods somewhere, even if only for a few months. Somewhere without network connections (i.e. leave that Starlink dish at home), preferably even without electricity. Live off the land, fish, hunt, do whatever it takes to get back to the essentials of existence. If this sounds absurd realise that plenty of people do this every year when they go out hiking, camping, canoeing/kayaking, sailing (although technology has made its inroads there) etc.
So, just install a nix and either add a single-function login which goes straight into a page-filling no-frills editor or use a tiling window manager without any window decorations or program launcher to get the same visuals. Add a restricted account if you need a bit more hand-holding to keep from checking your likes or twit-regurgitations or fill in the blanks. If you're hobbled by using Windows or MacOS you can achieve the same by creating a bootable USB-thing with a minimal nix configured to your liking. No need for new hardware (you're sure to have a suitable USB-fob around after all), no need for more consumption just to achieve less distraction.