My budget is 300€. What you linked there is Sony's lower quality rehash of their lowest quality Walkman before they scrapped that line. It only has 4GB non extensible storage and cannot play FLAC. I could find about 4 or so players which manage 24+ hours and Flac on my local (German) market atm, and they all have some sort of drawback. But the general state of the market seems to be "it runs Android and lasts 8 - 12 hours".