People have predicted Wikipedia's impossibility and demise from the start, and yet here we are, 2 decades and millions of articles in many languages later.

In reality the internet is full of systems with open participation. We don't see them failing notably more or less often than other systems. I think a (personal, mental) model that makes inaccurate predictions is possibly flawed, and may need to be revisited a bit.

If you've looked into Epistemology before, you'll see that Capital-T Truth is a slippery thing to actually define properly. Indeed, thus, Wikipedia makes no claim to being a Source Of Truth. Wikipedia makes a more cautious claim. It claims to be an encyclopedia: A tertiary source representing what primary and secondary sources say about a matter.

So if you keep that in mind, you are actually quite welcome to contribute to an article on theoretical physics. If you put in the work to study, track down sources, and understand what they're saying, then that's a good start. If you can then use that information to write a coherent text explaining the concepts, then that's perfect.

There's no magic fairy dust that turns you into an expert. If you work hard and do the same things any other expert would be doing, then how should we treat you?