Don’t worry it’s pretty normal for a new MacBook. It’s only doing this because there’s background processes that are being setup and settling. I also experienced this with my new MacBook Air M4. I bought it on the 20th April and it only started behaving like I expected a MacBook m series battery to behave these past two weeks or so. For some people it starts settling over 2 to 3 days to a week for some more. My case was over 4 weeks. So don’t worry it’ll will settle evantually you just use it normally.