Use value from buildForm() in submitForm() My buildForm() method queries the database and returns data which is used to calculate default values for the form. How can I use these values in submitForm() without querying the database again?
Typically, the $form_state object can be used to stash that data. $form_state->getStorage() references a simple array that you can put whatever you like inside, which you can then retrieve in submitForm() the same way.