Have you tried zerotier? Another option is to get a vps with unlimited bandwith and setup ovpn server on it. Then you need a router that can connect as a client to vpn. This way you will have a public ip and you dont need to mess with tunnel services. A vps with public ip is about 10 bucks a month.

DIY is like that. If you look up how to make a birdhouse they will tell you you need a saw, a hammer, nails, drill, paintbrush and something to measure with. Having a 3d printer and a soldering iron nowadays is pretty low entry, you can get into it cheaper that buying the saw, hammer and drill for the birdhouse. You don’t have to buy the bambulab printer and the weller / hakko iron. You can print this case on an ender 3 you found in the dumpster. Or pay 10 bucks for someone and they will print it for you. On the other hand you will have a device you can infinitely repair unlike the kindles that are kicking the dust every few year for everyone.