Data and wifi problem with my new iPhone 12

A little over a week ago bought a new iPhone 12 for myself and it was working fine. I then went on a week long trip out of town where I had access to no wifi whatsoever. At first my phone was working just fine but by day two I was only able to access messages and the Phone app. Spotify, chrome, YouTube, the app store etc, were not working. I checked settings and all of these apps and more were connected to my data. I checked my service, iPhone storage, tried to reconnect to my data, delete and reinstall apps (my app store wasn’t working so they are gone as of now) etc. Nothing is working. Anyways I got home today and connected to my wifi and it still won’t work. I tried resetting everything but nothing will work. My ipad and computer will…. But my new phone that costed hundreds of collars will not even work when connected to internet. My phone now is essentially useless. What do I do to fix this problem?