Then your calculations do suck more than anything. The G-Cards are weak as 🔥. They don´t have the same effects as in the Anime. They are not much harder to destroy than any other monster. (Only Obelisk with a little ressitance).
Nothing OP Ulle boy. That deck would not even work. If it were and you would summon Ra, Slifer or Obelisk, what than? A Mirrorwall and they are done. Congratulation on spending atleast 4 ressources for nothing. Shining Blue Eyes is better and even that card can´t survive this format.
Obelisk good in reality but effect bad. Osiris/Slifer eff good when u summon 2k or lower monster's are destroyed. And 2k more ATK monster ATK is decreased. Ra terrible. But sphere mode, phoenix mode is good.
Giant germ(possibly reward from yamimarik) - soul exchange and no problem. Or double summon u summon a monster and S.E? Or labyrinth wall skill, Haga's 2000 def monster or spell what give you two token..?