What’s the point of having unlimited data if you have to use Wi-Fi?

So what I’m understanding is that with my iPhone 13 Pro as sophisticated as it is, will not update unless it is connected to a Wi-Fi network which is not the same as my mobile data network which I pay a lot for & it is supposed to be Unlimited and 5G. I do not have Wi-Fi at my house. I do not use public Wi-Fi. I’m not going to a friends house to use our computer my phone up to it either. Is Apple going to fix this issue? I’m not the only one who has a problem with it, thank you.