Is it possible to enable key repeat for letter keys on the Apple Smart Keyboard for iPad Pro?
As far as I can tell this isn't possible, which is a shame. I was trying to use my iPad with remote desktop where I need to hold down keys and it just doesn't work. It seems this is a "feature" of iOS that only certain keys like space and delete are allowed to repeat. Here are some links about it that I found. 

https://discussions.apple.com/message/34220222#34220222

https://support-splashtoppersonal.splashtop.com/hc/en-us/articles/230005527-Does-Splashtop-support-Bluetooth-keyboards-