i have only the apple logo on my iphone

Hi,

Try

Force Restart 

Press and quickly release the volume up button

Press and quickly release the volume down button

Then press and hold the side button. When the Apple logo appears, release the button.

Force restart iPhone - Apple Support

Here --> If your iPhone is stuck on the Apple logo

An other things,

If you have full storage in your phone this is a common problem, you can try tu update your phone from a Mac or pc, remember, If you don't have a backup, the data may be lost.