trio's are generally very hard to balance,
and as such I'd try not to make one untill much later.
also, smaller decks are more consistent;
it takes on average less turns to draw what you need.
try to make your deck 30 cards, or at least as close as possible.
first of all, what are quantum pillars and nova doing in there?
Your deck seems to lack focus...
I'd personally look for another source of damage than graboids;
if you do, you can just remove all of the
-cards.
After that, try to focus your deck more: what strategy do you want?
You said you want to make a solid defense with armagio+otyugh...
now go over each card; does it add to the deck?
do you need momentum?
You have no other way of dealing with shields, so it may be a good option.
plus it can add to oty's HP; I'd keep it.
do you need enchant artifact?
a big part of the defense comes from armagio's;
there are no permanents that really need protection.
So I'd remove it.
Once your deck is smaller, you should add more copies from the core cards;
making a reliable strategy with very few copies is quite hard.
In this case, you'd probably add a few armagio's and one or two otyugh's.
Also keep an eye out for the quanta balancing;
both a low amount and a high amount of quanta will leave a non-optimal deck.
Also, note that modifying this deck can go a lot of directions,
depending on where you put the focus.