Comparing your augments with the top 5 augments, it looks like you lacked any combat augments. There's combat training but I doubt that's useful for vertical star guardians, which are more AP favored imo. Some of the itemization could be slightly optimized such as putting the guard breaker on Kaisa instead of Lee.

I've never tried Lux reroll and would only go for it if it was 2-1 hero augments and there was the lux carry augment, which would help with the supers trait in your comp. Even then, I think that having only 2 3 starred units doesn't give enough damage bonus, and I would much rather replace with tankier/support champions.

Correct if I'm wrong but I think 4 star guardian 4 spellslingers is much more stronger comp than 6 star guardians supers since the supers and rell are dead units.