Hello.
My suggestions are diferent to what have been told you.
First of all, if you play the two decks suggested, with all the cards upgraded, your winning mark it will not be higher than actual one.
What will improve your deck faster is using shards of gratitude, they help a lot early game and also against venom decks (you can take out purify without affectiing your performance against Scorpio and Morte with Shards) 4 shards ans 1 feral bond is good for decks about 40-55 cards. Also 5 or 6 shards without ferals bonds is more consistent but then it is a little hard to attain EM's.
Also, only one steal is needed indeed. Usually the main purpose of having a steal in a FG deck is helping against Obliterator early non-protected Pulverizer. Against other goods it helps(stealing one feral bond,useful shield, graveyand), but it is not game-deciding like it is against a earry Obliterator's pulvy, which is game breaking if you can't deal with soon.
Reverse time is not really needed, I have played more than 1.000 games against FG's with rainbows, and I can tell that only a very litle portion of them are lost by eternity being last card.
Two rains of fire are very useful against a lot of goods.
I don't know if you have tried eternity-pulverizer duo (without butterfly). For me works very well if you know when to put each in play and when to change weapon, and adapt to the drawing order, and it is more efficient and fast than butterfly effect.
Also, upgradint the cards that make it more cheap to play will help a lot.
About shields, I suggest you to put in one permafrost shield or one jade shield. Maybe two more phase shields (if upgraded to avoid been too heavy on aether quanta) are very useful and give you enought time to set up.
About the goods you hace problem. With Sogs and permafrost or two more phase shields, Osiris is an autowin. The sogs also help a lot against Octane, (and of course Jade shield). Seism can be done if you play towers one by one, sometimes he will rush you.
Divine glory and rainbow are almost imposible with this kind of decks unless they have a very, very ba draw and you have a very good one.
Hermes and Graviton, are also difficult, but you can improve results with the suggestion above. The same about eternal phoenix, it can be done,, but also it will rush you more or less half the games. Miracle is easy, maybe you have been unlucky against him. Sometimes if he starts with a lot of towers is dangerous, because if he is lucky engouth to draw some dragons after, it means a strong rush.
I hope this will help you a little. Enjoy this amazing game!