The decathlon lines are the weak link, I use https://www.metropolis-drachen.de/en/Accessories/Kite-lines/2-line-sets/Climax-Protec-set-2-x-25m.html
I would not recommend the Orao Feelr 180 for you, it is suitable for a beginner, I think the one you have is good to learn on.
Just practice, concentrate on small hand movements, big steps with with your legs.
Watch Johns videos see how he moves. Youtube has lots of videos on flying both types of kites.
On a dual line kite, learn to snap stall the kite, learn to give slack on the lines, learn to give little sharp pulls. (I have bought yoyos to practice hand movements with).
It just takes time, and good winds.
And if you are making good progress, that's the time to buy better kites. Prism, HQ, and Spider Kites are all good dual line available in Europe.
Kite forge, and Revolution are very good 4 line kites. I do not fly my Orao 4 line kite much now, I prefer 2 line tricks in light wind.