You cannot do that in the EU.
Also, phones communicate imei and other sim information, not OS information on the header plane during handshakes with the towers.
>interpreters, compilers, memory hierarchy
Those are nice if you want to do embedded and C. A complete waste of time for Frontend/Backend, mobile and desktop people in the beginnings.
Tell me why someone picking up Python/JS should learn the above mentioned things, rather than learn basic security principles and not pip/npm install blindly all the packages without checking the source? Change my mind.
Sure, patch your software, but you can keep accumulated feature requests on a separate branch. Then, as time goes on, decide whether you should rather monetize on an updated and more feature rich version, or just push updates and make people happy. I'd say there is more money in the first option, while the second makes me feel better. It's the developer's choice. Check https://www.holdemmanager.com/ how they do it.
For OP's kind of software, I'd say one time license purchase would be the most user friendly. So yeah, sell it like people did in the good old days, before the cancer that is SaaS took over the world.
I'd advice you to start exercising. I recommend kettlebell and weight training, not cardio. This will help with your chemistry and make you more confident in your abilities.
>I’m taking a year off to live off my savings and work on an idea, but I don’t have one
Why take a year if you are clueless as of what you want to do? Do some traveling and air your head. If you still cannot find something you want to do, go back to your 9-5 job.