Mazda2 2010 1.5L - Spark plug gap?

My Mazda 2 2010 1.5L (49K miles, automatic) has some kind of "delayed" acceleration when I drive on 30-35mph and release the gas pedal then press it again there's a 1.5~ second delay then I can hear the spark plugs igniting the fuel.

Idling is not great either and going up and down constantly between 600-800RPM.

What are the chances the spark plugs are the cause of these issues?
My throttle body was cleaned 3-4 years ago.

What is the recommended spark plug gap?

I can see many people use NGK 5464 with .044 gap while manual says .047-0.51 gap?
Will it cause any issues using .044? Should I re-gap them carefully not breaking the iridium tip?