Upgrade to which model?

Hello! I am currently using the iPhone XR. As far as I know, this phone has been with the family for 5-6 years. The ownership went from my dad to my sister and then to me. Right now, I am researching which of the latest iPhone models I should choose since my 21st birthday is around the corner!

iPhone XR specs:

iOS 18
Battery Health: 74%
Storage: 64GB (sitting at almost full storage, like 62-63GB)

I am a university student, and I use my XR as my personal phone, where I take and upload photos, play casual games (not heavy games such as Wuthering Waves), and listen to music. I am eyeing the iPhone 15 Pro Max, but I am unsure if this is the right decision.