Space Compression's hardest part was where he needed to harmonize all the things inside the sphere he created to compress the attack. There were different types of energy that would be absorbed along with the main attack, so Alex needed to find a way to harmonize them.
Luckily, that unique Space Element of his already sped up the process while the rest was handled by his Sword Qi and Spear Qi that cut any resistance while being suppressed with his Pure Fire.
It took him a long two months just to master it, which was still within his calculation. With this, he should still have one year and one month to master the two things. He thought this would finish in a jiffy, but then the difficulty ricocheted the moment he practiced a dimension type Space Element Art.