I am not able to export a good quality video for Whatsapp with 576 x 1024 resolution

Hi,

Would you please help me understand the settings required  to export a good quality video from AE or AME? I am not at all able to do so, my video resolution has to be 576x1024 and the file size has to be around 5 to 6MB, I am having hard time exporting good quality video. Please help me. Thank you.