2 ALAN
It was a bug, maybe before the patches? The shock damage is equal to 40 + 40*sp, multiplied by the corresponding coefficients. In general, writing damage taking luck into account is not entirely correct, especially magical luck (you still have to get it), moreover, it does not apply to enhanced spells.
So, calculate how much magic skill you should have.

I'm answering...
I'm not just writing all this for no reason... and I mentioned the hero by name: Veishan, he initially has luck and soldier's luck, under such conditions, of course, getting magical luck is an impossible task)).
You need to play not only as Necropolis, and if you write something, then write what you know.
Magical luck DOES work with enhanced spells...

And to end the argument, I sat down and played a map, unfortunately, in 3 castles of the Shadow League on the 5th level, there was Armageddon, so the screenshots will be with Ice Bolt.
The first screenshot is a hit with an enhanced Ice Bolt with luck and a +50% ice amulet, without the Chaos Magic skill on the EIGHTH day... the damage turned out to be 594.
The second screenshot, actually, the 5th week, the same enhanced Ice Bolt, amulet, luck... the damage is 1782...
The hero's parameters are 5-4-13-10, respectively, there is plenty of mana... skills: Chaos expert, Luck, Magic, sub-skills: soldier's luck, magical luck, secrets of chaos, master of cold, mana regeneration, secret knowledge, fluctuating mana....
I hope after this, the questions "how to deal thousands of damage with spells on the 5th week?" will disappear...

P.S. Unfortunately, I don't have Photoshop now (to rename the screenshots to .jpg), and the forum does not support uploading native screenshots from the fifth game, so I'm uploading them in an archive... oh yes, patch 1.4, I didn't want to launch the add-on, I played in the original on the Outlands...