No landscape after updating to 14.4

If you already checked to no avail that the lock icon in your Control Center is disabled AND if you alredy tried a "forced" restart of your iPhone (using these instructions Force restart iPhone – Apple Support ), your accelerometer might be broken. Make an appointment at an Apple Store or AASP and have your iPhone inspected.

Regards

Giulio

See this support article:--> Rotate the screen on your iPhone or iPod touch – Apple Support

Regards

Giulio

Did you read the link (written in blue, and clicking on it) that I posted?