Try this...


# Add Html Field

test_css = fields.Html(string='CSS', sanitize=False, compute='_compute_css', store=False)


# Add compute function
@api.depends('state')
def _compute_css(self):
for record in self:
    # You can modify the below below condition
    if record.state != 'draft':
        record.test_css = '<style>.o_form_button_edit {display: none !important;}</style>'
    else:
        record.test_css = False


<!--Finally Add the field in the form view-->
      
<field name="test_css" invisible="1"/>