I don’t know where you live, just wanted to say if you’re dabbling in this new hobby, make sure they’re not keeping logs after your contract ends. Your IP of today might still be traceable back to you, if they keep the logs for a fixed time after the contract ended. Or use protection.
Refurbished Dell 7390? ~$250 has an 13" display with relatively small bezels. I think if you want it even smaller, you’d need some mini laptop or a tablet or steam deck. But that has other downsides. And having a device with an full-size keyboard is nice if you want to type / code.