Well, suppose I were to employ the following set of tactics in an overall strategy to just blow the mage and his tower to kingdom come:
a) Establishment of Infinite Crafting XP
First, take controlled level loss. Drop a single level (putting you exactly one half a level backward). Next, spend all but the last 500 of the level's XP making things. Finally, use "Greater Restoration" to return yourself to the highest level you ever held. Rinse and repeat.
b) Construction of the Tsar Bomba
As we have access to virtually unlimited raw materials, we could presume to be able to construct a tower silo as a bomb casing (90 ft. diameter, 280 ft. tall). We could fill the silo with marbles (.008 gold a pop) enchanted with spells such as "Fireball", "Ice Storm", or "Sphere of Ultimate Destruction". Establish the spell trigger as a marble's destruction. This would amount to well in excess of 1 million marbles. Establish a small blast charge (say, gunpowder or alchemist's fire) in the casing to destroy the first few marbles. Let the spells which ensue destroy and thus detonate the remainder of the marbles.
According to my calculations, using "Shocking Grasp" (5d6), this would amount to somewhere around 1.7 quadrillion points of damage. Of course, I would need to use a non-touch attack, but still. That's the LOW end of spell damage. Alternatively, that much magical energy accumulating at a single point could hypothetically result in the construction of a super-epic wild magic surge the likes of which the universe has never seen.
The process of constructing this weapon, by 1 cycle per day, will take approximately 3.4 years. As we have the ability to suspend time indefinitely (within a pocket dimension), this does not pose an issue.
c) Alternate Uses for the Tsar Bomba
If, for some reason, the bomb turns out to not be useful as a weapon, hypothetically the Artificier in our party could use the marbles she created to gain a fundamentally infinite crafting pool and construct something else just as epic.
brought to you by our artificier.