I Pad Air pro 4 Glass Protector

I presume you have either an iPad Pro - or a new fourth generation iPad Air. An “iPad Air Pro 4” doesn’t exist.

A good quality screen protector, such as Zagg, should have little if any adverse effect on the sensitivity of your Apple Pencil.

iPad screens are robust, but the anti-reflection treatment and oleophobic coating can be easily damaged by tiny grit/dust particles that are unavoidable in many environments. The oleophobic coating is a chemical sacrificial layer that will wear-out over time.

A Screen Protector provides an additional defensive barrier - protecting both the original screen finish and the oleophobic coating. The downside is, perhaps, an increase in screen reflectivity and a slight reduction in contrast.

When using a finger, you can “feel” an abrasive particle - and will instinctively moderate finger pressure to avoid damage. The tip of the Pencil, by contrast, does not provide the same level of feel as does a fingertip. Contrary to what you might think, material science tells is that an abrasive particle will abrade a harder surface (the screen) before a softer surface (the pencil tip). This is because the abrasive particle will embed in the softer surface - and will be dragged across the harder surface.

Your iPad screen is an expensive component of your iPad; a screen protector is a sacrificial layer that is easy and relatively cheap to replace.

Some contributors here will suggest that a screen protector is unnecessary - whilst others may be more cautious, favouring the additional protection afforded by a screen protector. It’s entirely your choice.

yes it will

and well if it was necessary then one would likely be included, but on the other hand I had 2 ipads and both ended up with a hair line crack somewhere on the screen and I don't transport it or use it away from home really, non of mine had screen protectors