Every device I have ever owned without a screen protector has got tiny scratches on the screen similar to swirl marks on a car's clearcoat, no matter how careful you are with it. I have owned devices only ever cleaned with high quality microfiber, case since day one, etc. and they all end up scratched. Only way to prevent it is a screen protector. I've also seen a lot of people who say their screens are perfect, you put them in sunlight, and they are covered in tiny scratches, you just can't feel them with your fingernail or see them when the screen is lit. All it takes is one tiny piece of sand, dust, sediment etc. to get stuck in your cleaning cloth, tip of the pencil, or on the microfiber side of your case and you've got yourself a scratch.
I have a high quality tempered glass protector on my iPP 10.5 and there is zero difference in sharpness or touch sensitivity, even with the pencil. It does glare a bit more though but it's a small price to pay.
Buy a high quality tempered glass screen protector and I think you will be happy. Worst case scenario you just take it off, they are so cheap they are disposable.