Survival player here, so things may be a little bit different on Skyblock. A few ways to increase more damage is first normal enchants, yes. Custom Enchants also can help you increase damage in a few ways, by applying other status effects like poison or wither to your enemies, increasing axe sword or bow damage, or things like double strike which has a chance to land an attack multiple times.
Potion effects can also help you increase damage, especially the strength potion effect. Brewing strength potions or finding items like the Gorilla Club which give you a permanent strength 2 boost when held can help you do more overall damage.
Finally, leveling up your MCMMO skills for Axes, Swords, and Bow can give you additional damage or skills to increase your DPS!
Hope this helps!