According tocurrent documentation, a new web project should be created with--webapp flag. In addition to other bundles, Symfony UX Turbo is installed. No warning is given to a developer in the documentation regarding that this bundle affects the way the forms are processed in a controller:

Here is official documentation on forms processing which gives an example of a controller.

Here is how forms are processed with Symfony UX Turbo is enabled, which requires to alter a controller code.

This confuses a developer, who follows the official docs on Forms and does not get a form working. A developer has to investigate why no changes take place after form is submitted.