I know this isn’t quite what you asked however during the Covid crisis audible are allowing you to stream a load of audiobooks free. Including a number of Italian books. Check them out: https://stories.audible.com/discovery If you don’t want to follow a link just search audible free stream Covid

Why don't you try with "Ad occhi chiusi" by Gianrico Carofiglio? The language of his novels is modern and I believe it can be a good compromise. Just consider that the structure of a novel cannot be simple, as it tells a longer and more complex story, with many characters and details. You will have to be patient ;) Another option could be audiobooks by Radio 3 program Ad alta voce, that are now free. In that case, I would suggest "Sostiene Pereira" by Antonio Tabucchi, which is maybe more complex, though. Hope it helps ;)

Why do you need a novel? Maybe a set of short stories will be more easier to understand?

You could start from greek or latin myths written in italian for children. Intersting and meaningful stories, and each of them is not too long :)

I can suggest NOVECENTO or SETA by Alessandro Baricco. Or fables FAVOLE AL TELEFONO from Gianni Rodari or most famous elementary school book CUORE from Edmondo De Amicis.