The M4 chip used in the new iPad Air does not have the same performance as the iPad Pro version, thanks to core count changes.

iPad Air

iPad Air
The ever-common chip upgrade of Apple’s hardware lineup is always an improvement over the previous model. However, while it is often welcomed, not all chips of the same name have the same level of performance.
In the case of the M4 in the new iPad Air, it’s not the same chip as you would previously find in the iPad Pro.