Possible battery issue?

Hi all, I received my OnePlus 15 on Monday, and so far the battery has been kinda mediocre. For example, yesterday evening I charged it to 85% and it's already at 30% this morning despite only having 3.5 hours of screen-on time. According to this, I am getting less than 7 hours of screen-on time for a full charge? This seems a lot lower than the reviews were suggesting.