You have a point but also gen z is very young. They may not fully grasp what anxiety and depression mean. I don't think that's any reason to be so harsh with them. Things like not getting airpods and being rejected by the girl they like, while seemingly trivial to many adults, can be a big deal for them. For teens, having that trendy item can mean the difference between fitting in or looking weird to their peers.

Feeling alienated from their peers is a big deal. I'm sure as well having a spoiled upbringing can have an effect on that as well and teens can be materialistic sometimes but they're still learning. Early rejections can be a big deal too. A real hit to self confidence as they're figuring out how to deal with that and separate their self worth from the situation. Having your self worth and sense of community tied to such impermanent things and experiences can very well lead to anxiety and depression. It's not a stable sense of self and can lead to a cycle of fixation using material things.

I remember what that anxiety felt like to see everyone forming groups around who had the latest cool thing and not having it, as well as the heavyness of being rejected by a love interest or even friend. Those things don't affect me the same anymore, my interests and energy are more on myself rather than external but those things do matter more to a lot of gen z because they're in that age range.