I did a lot of reading about Franz Kafka throughout my life. He was born and raised in Prague but wrote about the greater world. He was, also, a Jew (who spoke German and Czech) who more identified with Bohemia and his own ethnic background. As such, he was a bit of a stranger in his own land. Yet that land was familiar to him. Before he died, he had hoped to emigrate to Israel. That's what I know.
We have studied Kafka at school repeatedly. The fact that he wished to travel doesn't mean that he was disappointed with Prague. In fact, his cultural/national belonging was so complicated that we are sure of only one thing: he was a Praguer, that's for sure. Prague leaves prominent traces in his work.
Obviously. I was striking an interpretation based on my focused university studies. It's not a put-down of beautiful Prague, but a statement about an artist's prose, his letters, and facts relating to his life.