in some cases I feel like Linux actually performs better than Windows on the same hardware

What are those cases?

Are you kidding? Proton is much, much more than “icing on top”.

To be sure you should build processor from a scratch and then write your own compiler directly in machine code.

Yeah, I know dangers of it, so this question for me is purely theoretical.

What do you mean?

My pleasure

Exactly. There could not be true / full ownership of hardware.
And yet that’s fine for me.

Now about that:

Today you can make sure the source code is truly what you intend, by running Linux on PC and GrapheneOS on Android. You might not have the ability to audit those, but others (like me) do, and are doing so.

Even in that case you can never be sure what a compiler did with the code. You can say: go look at the code of that compiler. But then how can I be sure it’s code had been compiled without malicious modifications. And so on.

By my question I mean:
Any hardware is made by some other people. Any hardware is work under a firmware, made by other people.

All that is a) regulated by licenses b) never can be trusted fully to work as you think it should work. Even if it based on open source - due to the “problem of untampered compiler”.

If you have no total control over your hardware, can you say you truly own it?
What percent of control is acceptable? How to measure it?

Do you have any plans to share your schoolwork with… well, school?

Can you truly own any hardware, though?