Why i cannot acsses the cellular

Start here:--> If you see No Service or Searching on your iPhone or iPad - Apple Support

If the issue persists (also after contacting your cellular carrier), contact Apple Support directly here:--> Get Support

Regards

Giulio

Ballen ~ Does your iPhone 8 Plus still have its original battery?

And what's the Maximum Capacity % here?...

Settings > Battery > Battery Health

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