So this thead got automaticly closed but not solved
I would be logical that if these both or at least the gform_disable_form_theme_css filter is disabled that the “block settings for styling also get removed from the wp-admin”
This is not a bug. In general, filters that run when a form is being prepared for display do not impact available settings.
You can suggest adding a filter that can be used to remove the style settings from the form block directly to the product management team for consideration when planning future releases on the Gravity Forms product roadmap page.