How do I deal with my materialism?

You strike me as a smart person, asking this question tells me that you are aware that something might be amiss. Here are my suggestions.

Donate everything that you have more than one of, with the exception of clothes and shoes, books, or other such items. Downsize. Be mindful, and be realistic about what you really NEED. Not want, NEED.

Volunteer somewhere where you are around those less fortunate than you are.

For your Birthday and Christmas in lieu of gifts, have people in your life donate to a charity in your name, or gather money from all and donate to your local food bank.

Asking this thoughtful question is a step in the right direction.

Materialism isn't really a bad thing unless it gets out of hand. We need balance and perspective. Only you know what form this "materialism" takes, Megan but from the quality of your posts on here I'd say you don't have a thing to worry about.

That is a personal choice and conviction .. It is a personal perspective and logic in terms of what you choose to prioritize