Some of those are actually sort of misleading.
There is no sin of Sloth. It used to actually be called the sin of Wan-Hope, which was the sin of giving up on God and good, for whatever reason. The word "Sloth" does technically work in the context, but it doesn't mean what most people think it means.
And the sin of Arrogance also isn't exactly what people think. It's actually the sin of placing yourself before God or thinking yourself better/more wise than him.
And of all those, Arrogance is the worst, while Lust is the least harmful.
It's significant to note that they are called the Seven Mortal Vices because by committing them, you are giving your soul a "mortal wound," so to speak. Those seven sins can easily lead you astray from salvation.
I would also like to note that most of the theology behind the Seven Mortal Vices is Catholic Sacred Tradition. Meaning that it does not exist in Protestantism.