Dear shahriar49,
sorry, but Sen2Cor doesn’t has an option to resample all bands to 10m. You misunderstood the resolution argument. The default processing without resolution argument provides you the four 10m bands at 10m resolution and all bands at 20m resolution (except the 60m band B01 and B08; see S2-PDGS-MPC-L2A-IODD-V2.8.pdf page 38ff). The resolution argument --resolution 20 skips the 10m processing for saving processing time providing you only the 20 m output. The resolution argument – resolution 10 skips the output of 20m resolution providing you only the four 10m bands for saving disk space if you are only interested in these 4 bands.
I see your point, but there is no fast solution. I can ask for adding the option providing all bands resampled to 10m for future Sen2Cor versions. Currently you can only proceed with a preprocessing resampling step.
Kind regards
BdPg