So I am level 16 and I have reached the valencina part and I noticed that the enemies in the skyway have 2k health. They also do a lot of damage to me and my companions. My question is if there is a place where you can go to level up your character that's faster than doing side quests?
I feel as though leveling up your character to be a little overleveled for an area is best accomplished through side quests. Even with the sidequests you wont get too overleveled (you can be level 70 at the end of aquila if you do all the sides). The tactic of finding an enemy to kill over and over to get higher level doesnt really work in my humble opinion.
Why are you fighting the enemies in the skyway instead of sinking the ships? Is your nautical level extremely low also?
I would highly suggest you go do those side quests, since they will help level you in both necessary experience, but if you are adamant about NOT doing those, then select an enemy and starting farming. Do you have a membership? Can you have a friend help you farm a dungeon or in Devilfish Hollow?
Side quests are your best option to level up. Don't dismiss even a small amount of experience from a quest; it will generally give you more experience throughout the quest, than when you turn in the quest.