59 cards in main deck are way to many.
I think this is way to inconsistent. You end up with starting with bad hands or "do-nothing" cards (e.g. Sparks). I advise you to cut them down to 40.
I think your deck is missing a go to win condition. What do you plan to summon to win the duel?
I would concentrate on the fusion cause thats is where Gem-Knights are really great. So i would remove some of the cards that dont support that or interfere with this playstyle:
- Gem-Knight Crystal: Requires tribute, not very strong
Furthermore remove all slow cards to make the deck faster:
- Gemini Monsters
- Alexandrite (eats up normal summon)
Gem-Knight function very well without a backrow and they have any good archtype specific traps anyway. All other traps are way specific to be used except Solemn Warning.
These are just tips and my opinion of the deck you dont have to implement any of this.
I play Gem-Knight for a few years now with my friends and its a very strong fun fusion spam deck.