I have 2 question about atack and Iv?

First ı wanna ask about atacks.
1)For example Blastoise is water type pokemon and has flash cannon whıch is stell type charge moves. does water pokemon use water atacks better or there isnt difference stell or water atack.
Another example dragonite is dragon/flying pokemon is it effective with hyper beam?

2)I have two gyrados one of them has %97 IV perfection and has twister charge moves and another gyrados has hydro pump but %80 perfection..Which gyrados will be better in game?

First ı wanna ask about atacks.
1)For example Blastoise is water type pokemon and has flash cannon whıch is stell type charge moves. does water pokemon use water atacks better or there isnt difference stell or water atack.
Another example dragonite is dragon/flying pokemon is it effective with hyper beam?

2)I have two gyrados one of them has %97 IV perfection and has twister charge moves and another gyrados has hydro pump but %80 perfection..Which gyrados will be better in game?

First ı wanna ask about atacks.
1)For example Blastoise is water type pokemon and has flash cannon whıch is stell type charge moves. does water pokemon use water atacks better or there isnt difference stell or water atack.
Another example dragonite is dragon/flying pokemon is it effective with hyper beam?

2)I have two gyrados one of them has %97 IV perfection and has twister charge moves and another gyrados has hydro pump but %80 perfection..Which gyrados will be better in game?