I think the advantage of the dual sims version is also to have 64GB instead of 32GB. I'm not sure if it's a good idea to use both sim cards at the same time, but I can't leave an extra SD card in the slot occupied by the second sim card...annoying because the SD card can have 200GB. Another thing, the installed language is...Korean, so it requires some resourcefulness to install a familiar environment! :)) As for the hifi dac, I have no opinion, not yet used, but for photos, I can say that the interface and the wide angle are really appreciable assets!

a dac always improves the audio quality, but yes if you are still using 64 kbs mp3s I recommend the 320.

FLAC format is more about appearance on a phone because unless you put on a 500 euro headset, it will be hard to hear the difference.
on the other hand there is always an improvement compared to the mp3, the flac having a level of volume higher than the mp3 that allows a listening with a lower distorsion.

I'm not sure if it's a good idea to use a micro SD, but I'm not sure if it's a good idea to use a micro SD, because it's not a good idea to use a micro SD, because it's not a good idea to use a micro SD.It would be a pity to stay with mp3, and to discover that the CD with which one has ripped it is now lost or in too bad a state to do it again