I think is kinds of "Need for cognitive closure".
It is diffrent with "Never trust anyone" and "Everyone can be wrong".
the NTA is make us can not to move forward. But allow the Everyone can be wrong makes we can move forward.
you can use the "Yocto Project" for making your own embedded linux distribution.
it will be hard to make the embedded hardware for mobile. nevertheless there is a product for user programmable devices, pine phone can be solutions for your needs
I have a desktop with similar specifications.
I used to build yoctoLinux at my company, but they didn't buy me a build pc, so I bought it with my own money and used it for my work. my efficiency has increased a lot.
However, after changing jobs, I didn't have anything to use, so I'm playing now. I think I should have sold it secondhand, but I'm just using it as a personal Linux server at home.
I've seen people make their own books in PDF files, get paid by PayPal, and sell them on their personal homepages. In the case I saw it, it was a bit like programming or Arduino examples.
If it's not at the platform level, but very small, I think you can do this, but reselling will be a little more complicated.
Even in systemd, there is enough sandboxing function, so I use it.
If we need to get away from version dependencies. I think we'll consider containers as well.
The idea was to list participants' purchase information in a byte array and hash them. I thought that the more participants there were, the more difficult it would be to induce the desired hash value to come out.
Do you have experience in development?
If everything is new, I think it would be good to approach python and study.
In the course of your studies, you will learn about some keywords and concepts in the field. Based on this, it may be helpful to find the next process in order.
There may be courses organized neatly for the desired purpose. Sometimes turning around can be more helpful.