Resd didn't boost popular red eyes deck we have now which is rez. Most of it doesn't even use any insight or spirit. Plus the card use in resd is completely different from regular red eyes deck. Cyber angels though do get boost by saffira. 20 sized card deck is too small for rez/red eyes deck to get any more boost or tech
I use a perfect GB deck and I don't win every duels. Even if these decks are great, you still need a good first hand and hope your opponent's is not that good.
GB isn't OP, I run it. I couldn't even get to stage 10 in the KC Cup, and I ran them due to the fact I don't have any Senju for CA. But hey, that's life.