2 things: 1st - I believe there is a peak that everyone will reach and never get back to it. I believe we all plateau once we reach our fullest potential, and once it's reached, you won't improve anymore. (keep in mind this is only for team-based modes). Dueling ofc requires tactics to win, tactics can be improved. And also hardware plays a big factor in improvement. Not sure why i'm explaining this but i'm sure you can understand what my personal opinion is.
You can absolutely continue to improve. Possibly the reason why some may think they plateau whilst genuinely trying is because they fail to recognise that improvement in non-linear. There will be times where you are improving day by day and there will be times where it will take a month to break past the barriers and even then the improvement is barely recognisable. We blame it on things we can't control such as our focus and our equipment. Equipment is a very minor part in your performance. Similar to how little a tennis racket will change a professional tennis player's performance.
There may be a limit to how quickly you can react and how fast and accurate your cognitive abilities allows you to twitch that mouse to a successful shot. (I still believe there are ways to improve these cognitive limits - see Binaural Beats). But you can most definitely improve your style and improve adapting your style to other opponents. For Team-Based modes I'd argue these tactics are even more important and more dynamic. Player awareness, awareness of opponents health and awareness of your opponents skill and how much they can handle vs other opponents etc etc etc....
Simply write down everything you observe. You learn a lot. (Yes, I've done this before).
Good luck... **hades**
Statistically, there's a 99% chance you'll never meet your life aspirations. Good luck!