Zagg Slim Book Keyboard Case - Screen Scratching

Anything can and will damage the screen unless it is designed not to touch the screen.

I use this on my MBP and it's been marvelous, but do not know if that will work with an iPad (although I saw they offer a sleeve):

https://www.radtech.com/products/screensavrz-macbook-pro-keyboard-cover

You might also consider a glass protective cover - I use this on my ipad Pro and it's great:

https://www.zagg.com/us/en_us/invisibleshield/apple-ipad-pro/invisibleshield-gla ss-apple-ipad-pro

I opted for this keyboard because I can use it without attaching it or clamp it on if I want to:

https://www.brydgekeyboards.com/products/brydgeair-apple-ipad-pro-9-7-keyboard

If you look at the pics you can see that it has little rubber bumpers in the lower corners so it does not touch the screen.

I used the slim book on my mini for over a year and never noticed anything. That said, I also used it with a zagg screen protector so that may be a viable option for you (as suggested by babowa)

Prior to that I had a screen protector on my iPad 2 for years and never got a single scratch on the screen. I know Apple doesn't specifically recommend screen protectors but I personally think if you're in a situation where you're going to constantly have something touching the screen they can be very helpful.

(on a side note I hope you registered your slimbook for the warranty with Zagg. I went through 3 of them before I stopped using it. As a company they do back their stuff, but every once in a while everyone makes a lemon)