@NAMcMahon I never got your elaboration.

My advisor doesn't prevent me from collaborating with others, it's the exact opposite, they encourage it. My biggest issue is that I don't have someone else to discuss ideas with. I tried to reach out to other researchers, but it seems that they were uninterested.

@AdamPřenosil How do I go about finding a co-supervisor? Is it appropriate to cold-email other researchers and just ask to work with them?

@Bryan_Krause, I don't think my post is meant to convince you of anything. Also, I am not claiming that my supervisor is incompetent. They might be the best particle physicist in the world. I am saying that they aren't proficient in my specific field as I am having to explain undergraduate-level concepts.

@Bryan_Krause, I don't expect my supervisor to be to able to tell me which ideas are good. However, based on my experience, I believe someone with more experience would be able to immediately rule out some ideas.

@gnasher729 You can use any book or webpage, but you cannot ask others for help. That includes coursemates, friends, family, forums, etc.