Your standard is too high. Counting staples as impure? That’s a little much, now isn’t it? Evil Eyes might fall into that category, maybe, but tell me: what TCG decks are “pure?” They all run staples. By your rules, almost no extra deck is truly pure. Set your sights much lower, and you won’t be disappointed.
I did a BE deck with exactly 0 spell/trap. Just monsters. And I had close to 7-8 win streak on legend rank.
Even though I initially made the deck to lose on purpose in hopes of going back to Silver League.
Konami should allow us to rank down to bronze like before.
Your deck wasn't pure enough, because it didn't consist of ONLY three copies of Blue-Eyes White Dragon. Therefore, it wasn't a pure enough Blue-Eyes deck.
How darest thou use a fourth-rate deck, you third-rate duelist.
First of all concentrating current could not be played alongside overflow anymore unless you go 1/1. But concentrating current is like an electric card, and cyber dragons are machines, also electric, so it's actually on theme.