Zweig was hopelessly delusional about what was actually going on, especially when so many of his contemporaries (Kraus, Musil, Broch to name a few) understood what was happening.
With regard to Vienna, Fröhliche Apokalypse(The happy apocalypse) is probably much more accurate than Zweig's cosmopolitan dreams.
They could've, but tbh its just very hard to read the memoirs of a guy who is extremely privileged, uses his family's money to travel around Europe just as it is ready to fall apart completely, and he is just stuck in this cosmopolitan idealism.
I've found Mann to be absolutely insufferable for the exact same reason(although both are very good writers when one only considers literary skills and ignores the actual themes).
With regard to Vienna, Fröhliche Apokalypse(The happy apocalypse) is probably much more accurate than Zweig's cosmopolitan dreams.