A champion actually based on balance.

I've been toying with a kit in my head that I would like to see added to the game, and as of lately, a lot of champions seem to have a huge amount of passives on their actives, or even straight up double passives, so I don't think that anything I come up with will be too ridiculous. I'd appreciate feedback and help designing what the champion thematically would look and act like, as this concept as of now is purely based around the mechanics and power fantasy.

Core position: Midlane or solo lane. Strong against lane assassins, weak against lane mages.

Core fantasy: Mage that turns the tables on assassins.

Basic attack range: 550

Passive: Damaging an enemy that does not use mana restores 25% missing mana. Damaging an enemy with a shield grants a non decaying shield that absorbs 100-510 damage (scaling by level) The shield amount granted by the passive cannot exceed this limit.

Damaging an enemy that both uses mana and does not have a shield deals bonus damage scaling off of their missing mana.

Q: Fires a beam that travels 900 units with a width of 375 dealing magic damage. This attack cannot be blocked by projectile blocking abilities. Static Cooldown 12 at rank one, 4 at rank 5.

W: Emits an AOE shock wave in all directions, emanating from the champion, with a radius of 500 units. The shock wave deals magic damage and knocks back enemy champions.

E: Passive: Whenever a champion within a 1400 unit radius casts a dash, blink, or teleport, the ability gains one stack that decays over the next seven seconds. At two stacks, a zone with a radius of 500 is created around the champion which erupts dealing magic damage, interrupting channels and dashes, and stunning all enemy champions inside for 1 second whenever a dash is cast. Zone stacks are refreshed when another dash beyond 2 is cast.

Active: Dashes 450 units at 750 (+60% movement speed) Static Cooldown 10 / 9.5 / 9 / 8.5/ 8. This adds one charge to the passive portion and can trigger the passive.

R: Gain a shield equal to 200 / 300 / 400 (+ 150% bonus AP) for 2 seconds. Draw in all enemy champions within a 550 unit radius, causing them to be knocked towards the caster at a speed of 1000, dealing magic damage equal to 200 / 300 / 400 (+ 150% bonus AP) Cooldown: 80 / 55 / 30. Drawing in enemies counts as a dash and adds one stack to the e passive. This ability can be cast while under the effects of knockup. For the next 15 seconds, the champion gains 50% bonus Magic Penetration.

This champion I believe is balanced, as there are crazier things in League at the moment, and this champion has some clearly defined strengths and weaknesses. I'd appreciate help with balanced damage numbers on the qwe abilities so I can preserve the fantasy of bursting down lane assassins, while struggling against ranged, mages and tanks.