At the same time though, the new Turkish state pushed universal literacy as a policy goal and invested enormously in it in a way that the Ottoman empire didn't

At the same time though, the new Turkish state pushed universal literacy as a policy goal and invested enormously in it in a way that the Ottoman empire didn't at all. It's very difficult to extract from data of that period (which may also have been manipulated for political purposes) how much of that change as due to the script vs other factors. While I don't think it's controversial that phonetically written languages are easier to learn at first, nor that the Turkish Ottoman alphabet based on Arabic was not ideal for writing Turkish, I don't think it was uniquely difficult. I think it's about as difficult as writing English correctly using our alphabet, which is to say it is harder than Spanish but much easier than writing Chinese languages. Note that literacy rates in Arabic speaking parts of the Ottoman empire - most of it - where the script and the language matched was also low. You can make the argument that Arabic diglossia was responsible for some of that but still)