As some one who's done their PhD in 3 years and supervised PhDs for 10 years:
1 - Cut the crap
It's easy to get overwhelmed with all the papers you read, so many topics, so many possible directions to go in. You need to focus. I suggest you start your first paper right now. From all the research you've done, what's a small topic where you can contribute? Make a list. Pick one. Start there, decide what more research you need to do to turn it into a paper, do the research, write it, publish it.
I did exactly that after 1.5 years in, and really just by fluke. My paper wasn't even exactly aligned with my main research topic, yet it did wonders in getting me going.
2 - Chunk it
Once you've written you first paper, keep going. If you get to five published papers, you're done. And the great thing is that you have your PhD already mostly written, just fill in the gaps, thesis done. It may seem counter-intuitive as you want to answer the one big question, but trust me, once you chunk your big research into little topics it becomes a lot easier. And you figure it out along the path. Build on each paper, you'll get there. You may even not get to answering your original research question fully, but with 5 published papers, who's going to argue with you?
3 - Ask the experts
Talk to other lecturers, researchers even outside your faculty where it fits. I had some problems I couldn't solve. Turned out most of the experts in the field at my uni hadn't got a clue either. Until I found one who did. Go to conferences, make connections. That'll also help you in your post-PhD life. Don't give up, someone out there will be able to contribute something quite valuable.
4 - "Trust your instincts, Luke"
The brain works in mysterious ways. I chewed on a problem for a year. Then, one morning in the shower I solved it. This is just how it happens. There's a physicist who said, "men who don't shave can't solve problems." Times of self-reflection, that's when the ideas come. If you could figure the answer out in a day, they wouldn't give you three years. And I'd fit in exercise, even just go for an half an hour walk. Lot's of famous people got their ideas that way.
5 - Get off the hamster wheel
I certainly didn't work hard, yet did it in 3 years. There are students working 14h days including weekends. And they take 5 years. Why? Because all their doing is running on a hamster wheel. I had a student who went kite surfing every afternoon and did a great thesis in 3 years. Why? Because he focused on the finish line. It's easy to get caught on the hamster wheel. You're doing work, right? I spent 14h in the lab today, well done, pat on the shoulder. The reality is, if it's not helping you to get to the finish, you're wasting your time. Stop self-gratifying work, do the hard stuff, the work that'll actually get you there. And if you don't know what that is, figure it out. Yes, it's harder than just sitting down and doing "something". Take a snapshot of what you know and make a plan from that. Keep checking your progress against the plan and modify the plan as necessary. And that links back right to point 2 - if you keep pushing out papers, you're making measurable progress. Plus, you build confidence that what you're doing is actually valuable. You got proof in print.