What should I do if my iPhone storage is full and I cannot update?

Unfortunately, there are no shortcuts here. Work you way through this Apple Support troubleshooting document to see if you can find the real culprit.

Your chances of success increase if you have the ability to connect the phone to a computer for the update process.

If your iPhone or iPad won't update - Apple Support

Did you clear your cache, delete history, power off and then back on your phone. If so, try to allow the update to be installed later tonight. Be sure to have your phone fully charged. Good luck

I think that a security update is more important than anything you have stored…Perhaps,🤔 if you don’t update you’ll lose everything you have😬Please consider clearing and making storage available for your update. It’s not very big.

The update is really small. Please consider making room for a security fix before you need it!

A very, very long time ago, I had a virus that would not allow me to update any security patches, nor would it allow me to delete or clean out the culprit…Thankfully, those days are over, so far.