Hello Thomass,
I've only heard some of Dohnányi's recordings, mainly his Mahler (which won't surprise you
)
To be frank, Mahler is not ideally suited to Dohnányi. There is transparency and objectivity, proficiently played, on the whole decently recorded, but it doesn't feel quite like Mahler. These recordings, including the Ninth, do not carry enough passion, and lack fantasy. It sounds, at least to me, very calculated.
To be fair, Szell was better in Mahler, but not by much. Szell and Bernstein were contemporaries, but their respective interpretations were miles apart. Just a comparison.