My S21 Ultra 512GB seems fine. 5G mobile data, 120Hz WQHD+ with 6 hours screen on time, 53% battery left. Been using buds Pro for a few hours and browsing/gaming. Had the phone for 4 days now and battery life is improving each day. Compared to my S20 Ultra, its been about the same or slightly better. Think that's good for a new release phone without a years worth of optimisations like the S20.