Hello Davide
I have RPI4 4gb with 3 installed. I am on free 15 day trial of Premium. I cannot activate Resampling. I switch it on, enter the sample rate and bit depth, save it and I am still getting 44k 16bit output according to the Volumio UI and also my DAC. My files are stored on a USB HD in AIFF and play fine. However my particular DAC ,a DDDac 1794 with the Luckett WAVIO USB board, sounds better to me when resampled to 176khz 24bit. I have tried to find out if the Resampling feature is active yet in 3 but have had no luck.