eSIM option unavailable on iPhone 13

I have an iPhone 13 (model for the European market, NOT china, HK or Macau), currently on iOS.3.

I have used eSIMs before updating to iOS 18 and it worked fine, I did have some issues deleting the eSIMs after they expired though (it did not want to delete and I had to update my phone for them to disappear). However, ever since I have been unable to add an eSIM. I just bought one today but it will not directly install, nor manually as in the Cellular data page in Settings there is no Cellular Plans section. I have tried resetting, airplane mode, reset network data, nothing works.

I also tried to update to iOS 18.7 and iOS 26, no success, my phone gets stuck on “Verifying update” for hours. Also unsuccessful with a laptop.

Any suggestions are very welcome. Both issues are concerning and i dont know what to do