Creating a custom field populate with gravity forms and Gutenberg not working

Hi,

I tried your code here, but nothing appears to be stored in db ;
https://support.metabox.io/topic/select-a-gravity-form-to-assign-to-a-cpt/

print_r($meta); is returning nothing

$post_id = filter_input( INPUT_GET, 'post', FILTER_SANITIZE_NUMBER_INT );is returning nothing

Then, also for $saved_form = rwmb_get_value( .... ); which is NULL

Thanks a lot,
Best regards,
Wilhem