I can change it whenever I want, but I don't want to wait 2+ weeks again nor to pay 20+ EUR for a case. The one I have does the job nevertheless. No, I don't have a 3D printer.
Dude, you can print the case anywhere you want in your local area for few bucks 
I am sure you can find bunch of ads from people and services who are offering 3d printing services, most I know are 3d designers or just owners of 3d printers.
They don't even know what they are printing when I order it from them, it's dirt cheap and I don't have to wait more than few hours or a day for delivery.
Seriously though, why isn't an RNG generating true random results, and if it isn't, which opens up a philosophical question, why does the TRNG, indeed, generate true randomness? To be precise, urandom is a Cryptographically Secure Pseudorandom Number Generator (CSPRNG), and to be honest, I'm a complete noob when it comes to this field, but I somewhat agree with this perspective.
It's simple math, and if you are not mathematician you can't understand it.Companies wouldn't waste millions of dollars to achieve true randomness if gameboy, nintendo or raspberry pi was able to achieve this.
Research this subject deeper to understand it better.