Obviously as a coach I believe that the quickest way to achieve 1000 would be to learn the fundamentals from someone more experienced than you that can also identify your shortcomings, that being said, I wouldn't lie and say you couldn't easily get there on your own without the direct help, albeit likely slower depending on your approach.
Chess books or specific courses are unlikely to help you cross 1000. The main reason why a coach is beneficial to you is because they can tell you what to work on and explain where you went wrong in a catered manner. A player can't know what they don't know, which is where an experienced coach would come in handy.
The main components of crossing 1000 is are you fully focused during your games? And are you following good checklists like "Why did my opponent move there? What's his threats? What changed about the position? What squares weren't defended before, but are defended now? Am I or him in danger? Does the move he made hang any material? Is the move I'm about to make hanging material? Am I improving my worst placed piece? Am I following the game plan of my opening? Did I look for checks/captures/attacks." etc etc.
A coach is a surefire way to make sure you're asking yourself the right questions since they know the correct methodology. If you don't wish to explore that avenue, I would suggest doing some introspection on your approach since you've been stagnated for a while and see if you can Identify what is and is not working.
I feel like I have been playing for a while now but not making significant improvement. Should I start reading books, taking specific courses or get a coach?