First off your money your decisions. But it seems you’re struggling with this decision because it’s not you and just to impress others while trying to feel comfortable. Your confidence is what makes you comfortable.
I’d like to think regardless of how much I make there are some things that I won’t get the value out of. A 100 t shirt is one of them.
I think if struggling with this concept and it’s for others not you invest your new wealth. Unexpected life changes may happen. You can then when you’re ready either invest in these new status clothing or what aligns more with your core beliefs. Best of luck.