Regarding finding a network:
If you see No Service or Searching on your iPhone or iPad - Apple Support
But also:
Marshl13s wrote:
Since the most recent update my phone has randomly required a restore for no reason (in which I lost a year of photos and contacts)
Your remark in parentheses does suggest a reason:
Is your iPhone storage full? Check Settings > General > iPhone Storage and be certain you never have less (hopefully much more) than 10% of the iPhone's total storage free.