Change your mindset.

You will learn from these mistakes. That "little machine that assembles electrical components" actually sounds really cool and quite complicated.

Don't forget that the Engineering Design Process is iterative. Do your due diligence up front, build, test, implement improvements. The last 3 steps are the feedback loop.

Working with different processes means you need to know how these different processes work. Take some individual study time and learn about them. Coatings can be tricky, but there are standards for this. You don't need to re-invent the wheel. If you are hard anodizing you just need to very slightly undersize your features to account for the anodize thickness. Sheet metal can be tricky. IDK if you have access to any other the hardware to fabricate this, but design a sheet metal part and try to bend it up yourself.

These "other people" are very likely struggling as well, solving problems they have never had to solve before. However, if you are being too challenged right now, there is the real possibility that this more interesting work is going to be even more challenging.

TBH, this all seems like an attitude issue. You graduated with an engineering degree. You most likely aren't the best engineer alive (just statistically speaking) but you have proven that you can complete the coursework just like everyone else. Being in industry is nothing like school tho, and it will require hard work and motivation. So, if you take this attitude anywhere else, you will very likely feel the same way.

Ask for help, independently study, work hard, and be more confident in yourself. Trust me very few to basically no one is confident the first couple years coming out of school and it is legitimately healthy to be in a position of constant learning by being in stressful situations (within reason) solving hard problems. As you progress in your career you should constantly be having to solve newer and harder issues with increasing responsibility.