I would like to use wpcf7_form_action_url
filter and change action in form.
To be able to do this, I need to disable the AJAX which is used when submitting the form
define('WPCF7_LOAD_JS', false)
is not a solution because WPCF7 AJAX
is packaged into an entire JS flag - so this will also turn off JS validation
if WPCF7_LOAD_JS JS is disabled, it will take the input to the server, validate and return to the form and show the errors. So, I think you not losing any validation functionality when submitting the form.