Your character's already got pretty much all the best items. I don't think you really need help at all. Still, I would recommend putting away your extra guests and putting into your active inventory New Year's Surprise and Arms of the Dragonguard/Dragonguard Invocation (Pure Mages can use both. I know you don't have either, but your character has so many P2W items that I think I have good reason to assume you have a spare UR GGB). Its accuracy may be a problem for heals, but Cometoid Jelly is more useful than your damaging pets in a Pure Mage build.
I believe you know what you're doing with your weapons and armors. The former shows a level of customization that indicates a purposeful decision, and the latter is clearly to maximize damage and show off (Sinmaw). I don't really know what's going on with your shields, however. Why do you have three compression shields? While shields often have weak effects, it's still not great to use this many compression shields, which have no effect, when you have the space to have a shield with an effect on all eight slots.
Finally, your miscs are totally fine, but I'd recommend picking up Z-finity Gauntlet: Power while it's still here. It lets you inflict a universal elevuln, which will massively boost your damage without conflicting with Blood Contract.
There are multiple ways to deal with damage caps. One is to use a high hit-count spell or armor to maximize damage. Mages often use Fireball Z with Pyromancer's Robes since the spell does 15 hits. Another more niche way is to cheese the fight by stacking Fragile, which completely bypasses damage caps. The final way is to just play more defensively. A well-equipped character shouldn't be a one-trick pony that can only win by nuking.
There are several things people use to play more defensively.
First, the Dragonlord Shields have the incredible effect of QC HP Shields, which completely block all damage to a point. They can be clicked on infinitely many times per turn, though the cost increases with each use, so there is a cap once the cost is greater than your entire SP bar.
Second, people may use Paladin (and Necromancer once its elite armors come out). These two classes were recently revamped and are among the most powerful armors in the game. Paladin comes with its own equipment, and it has a skill that changes all attacks by the undead to damage its lowest resistances. This along with many other skills makes Paladin the ultimate undead killer, and because we have Zorbak Ally Assist, this can be extended to almost any boss. Paladin can also charge up a resurrection skill that gives you a second chance if you mess up, and Necromancer has its Deathwalker form as its resurrection, which is generally considered inferior to Paladin's own resurrection. Regardless, both classes provide great sustaining power with heals and status effects. You should definitely level those classes up and try them out for yourself.
Third, people can just play the way the game was played in the old days: sit in an armor of the proper element with the proper shield and just attack until the monster dies. Relatively few monsters do multi-elemental damage, so it's a viable strategy.
Fourth, Alchemical Unity allows you to inflict very strong blinds. You can become literally untouchable and just attack until the monster dies.