iPhone 14.4 update

I try and update my iPhone X from 13.3.1 to 14.0 but whenever I click on software update in general it gives me the error message: Unable to Check for Update An error occurred while checking for a software update.

So then I tried to update it from the windows iTunes app, then iTunes tells me The iPhone could not be updated. An unknown error occurred (4000).

After that, I searched it online and all of the 'fixes' I tried didn't work so now I'm stuck... any help?