Absolutely, creating a complete modern computer is an incredibly complex task. Building a 3GHz CPU from scratch is a monumental challenge, and even assembling components like stm32 or Pis requires a level of expertise. Developing your own drivers, dealing with various peripherals, and ensuring compatibility is tough shit.
However, once the software is written and released under a Free Software license, it will be there forever. As you’ve already stated, it’s hard, but not impossible. I share your hope that one day we will reach the point where such endeavors become more feasible.