My brand new iphone 15 needs to be charged everyday. And i don’t even use my iphone that much. Is this normal?

Check your battery setting to see what apps may be using a lot of battery…especially those that may be doing a lot of background use. Check your settings overall. If a lot is going on in the background that can be a big part of your issue. Normal is subjective based on each individual’s settings, usage, apps, etc. So it’s impossible to really answer what is or isn’t normal without knowing all of the information. You can also contact Apple directly for troubleshooting to help determine what may be going on.

I've had the same experience with my 15 pro - in fact, my experience is so similar to what you describe, I had to make sure I didn't post this.

This is the first new phone I've gotten since the iphone 8, so I was looking forward to not having to charge it every single day :-/

I'd say my usage is moderate, and it still drains the battery doing simple things like listening to a podcast, or doing a few spanish lessons in Duolingo :-(