i wanted to know, why is the nine-tailed लोमड़ी, फॉक्स hard to deal with and to control than the other kuubis?

The other demons are called bijuus not kuubis and the reason is because kyubi is the only one of the demons that has a invincibility बरसती, लबादा and it also has the most chakra out of all of the bijuu

Not exactly Kyubi means Nine-tails it's correct but each biju has a different amount of tails and their chakra level may be different but its not known. Now to answer your सवाल each tailed beast is different it all depends how they've lived their lives how they have been treated द्वारा the villagers and what they've been called the Nine-tails has been called the Nine-Tailed Demon लोमड़ी, फॉक्स and he has had a rough life so he has become a being of pure hatred so that's why he might be one of the hardest to control but read the latest मांगा and you'll see what has happened with the Nine-tails.
These are the name दिया to the Biju:
1 Tail-Ichibi
2 Tail-Nibi
3 Tail-Sanbi
4 Tail-Yonbi-Son Goku
5 Tail-Gobi
6 Tail-Rokubi
7 Tail-Nanabi
8 Tail-Hachibi
9 Tail-Kyubi-Kurama
10 Tail-Jubi