return { 
                'type': 'ir.actions.act_window',  
                'name': _ ('My Order'),  
                'res_model': 'purchase.request',  
                'res_id': data.get ('order_id'),  
                ' view_type ':' form ',  
                ' view_mode ':' form ',  
                ' target ':' current ',  

                 'context': {'no_breadcrumbs': True},                 

                'nodestroy': True,}
                

Hopes this helps .. !!

https://www.odoo.com/es_ES/forum/ayuda-1/question/hide-breadcrumbs-on-specific-model-123540#answer-170409

Try this:

def custom_main_button_action(self):
  ...(my stuff)...
  return {
          'type': 'ir.actions.act_window',
          'name': _('My_Name)'),
          'res_model': 'my_model',
          'view_type': 'form',
          'view_mode': 'tree, form',
          'target': 'current',
          'clear_breadcrumb': True,
          'views': [(tree_id.id, 'tree'), (form_id.id, 'form')],
    }