system
Given the following post, respond as if you're commenting on Reddit:
human
At the verge of quitting. I feel like I learned nothing in 3-4 years of my PhD and start to think I am the problem.

Dear comrades, I am a PhD working on S-composites as cathode materials for Metal-Sulfur Batteries - since I don’t know where else to pour my heart out, this is my story. 

Since my Masters I was interested in electrochemistry, especially in the field of (post Li-ion) batteries, and have to say that I am a „family person“. I get along very well with my siblings, my parents and my wish to have them in a distance that I can overcome within an hour of driving resulted in me choosing one of the nearer universities. Despite the fact, that there are other, farer universities that have more expertise in my field of interest. A choice I regret nowadays, a lot. 

My professor has a very broad scope of topics to offer for PhD students, let’s call them A, B(attery) and C. The B(attery) topic is something he stumbled upon by getting a PhD from an industry company that was interested in this field. For A and C the story is different, these are topics he either worked on during his own PhD or in the course of his PostDoc. And he has a LOT expertise herein.
This interest of said cooperation/company in topic B was at least partly passed on to my PI, even though he himself rarely or never became actively involved in the topic and still does not do so. Nevertheless, he always claims to be an absolute expert in topic B, even though there is no publication of our research group that has been published above an impact factor of 5-6 so far. He is at a level of knowledge where, even after over a decade of R&amp;D in the field, we as students still have to constantly explain to him the elementary parameters by which these battery types are evaluated for quality and he has little to no understanding of even the elementary measurement techniques.

Now to my problem: I feel like I have learned nothing in 3-4 years of PhD and also never had a network to learn or benefit from in any way. Don't get me wrong, I have put a lot of effort into my research, read papers to the point of no return, developed and implemented my own ideas (5 co-authored papers published and currently 2 first author papers in progress), co-authored research grant proposals, supervised and corrected exams, supervised 5 students during their master thesis or research internship, worked out basics on measurement techniques (new to me) myself, was at a particle accelerator (SLS Switzerland) for the first time last week for an in operando measurement on prototypical batteries, which I planned, set up as well as applied for, in some major parts, completely on my own, etc. So: With none of the things listed before, nobody ever even helped me. Not my professor, not my colleagues, no one. No one cares what I do on a daily basis, and yet, in everything I do daily in my own research field, I find that I feel like a novice compared to the "big guys in the battery field". 

Here I am, comparing myself to my supposed "competitors" from other universities who are really well-versed in the battery field, and I feel like I am worth nothing. No matter what job I applied for now towards the end of my PhD resulted exclusively in rejections because someone was better, more accomplished or more experienced. I will never be able to make up for what these students learned in the course of their PhD through their network and their professor. I feel like I lost 3-4 years of time for nothing. Looking at my data feels more like "Jugend forscht" (research program for pupils) than professional science to me. My contract currently runs until the end of July 2022, I wanted to use the time until then to round up my started ideas and topics. Nevertheless, I am shocked to see that I am constantly treading water and am not making much progress on anything at the moment.

Am I the problem or should a PhD student become an expert in his own field even "without an internal network"? Right now I have the feeling that no matter what I desperately try to finish, it will always result in a technically subterranean dissertation. Over 8 years for a academic career and I have the impression this was a pure waste of money, resources, lifetime and nerves. Fu**.
gpt
I mean from the sounds of it, you've learned how to do research independently? The thing that is frankly the thing you are meant to be able to do post PhD?

There will be a wealth of transferable skills from that. You have several papers to evidence this. The fact you got time on SLS means you can write persuasively about Science as well, enough to warrant time amongst thousands of yearly applications. On top of the rest of the stuff. 

So, don't sell yourself short. The skills you've learned will take you further than the specific knowledge, so long as you actually take the time to appreciate it.

Keep going, and don't let trouble job hunting trick you. Finding jobs is something of a bastard right now, especially in academia.