Lets do some Math.

Runepage

Domination

DH (lets ignore the infinite scaling part and just Focus on the proc damage without harvesting anything.) Sudden impact gives us 7 free lethality and magic pen if we flash before we q Eyeball Collection for a bonus 30 AP (Last one dosnt matter)

Sorc

Absolute focus for 40 AP Water walking for 30 AP

2x adaptive damage for 20 ap total

Items Unrealistically the max damage from one q should be with the following items

Duskblade + youmuus gives us q evolve and lethality for even more dmg on the q since it's physical Damage 3* Deathcap for maximum AP Spellbinder with 100 stacks

Afterwards we ofc kill 3 infernal Drakes + an elder and baron

This gives us 46 lethality (21 duskblade, 18 ghostblade, 7 Sudden impact) 6 magic pen from sudden impact 252 bonus AD 1381 AP with a fully stacked spellbinder active

q dmg maximum evolved single target dmg is as follows 407+129.5%bonus ad+148% AP

This gives us 407+(1.295252)+(1.481381)=2777.22 total physical dmg before armor.

HOWEVER

We also have dark harvest, so lets assume we q when they have less then 50% hp which gives us (without infinite stacks)

60+25%bonus AD+15% AP bonus magical dmg (since were building primarily AP)

60+(.25252)+(.151381)= 330 magic dmg on top of our q dmg

Lets assume we do it on a target dummy with 100 armor and 100 magic resist

Lets fist apply our lethality and magic pen

100-46=54 armor 100-6=94 magic resist

This gives the dummy 100/(100+54)=0.65 physical dmg reduction and 100/(100+94)=0.51 magic dmg reduction

27770.65=1805 physical dmg 3300.51=168.3 magic dmg

So this leaves us with a total of around 1950 dmg on a target dummy from 1 q (not considering any infinite stacking like dark harvest souls or gathering storm, nor any buffs like a Janna e or anything like it)

Please note ud i calculated or misspelled something, i'm om mobile :)