Thank you for your answer.

I hope I am not missing anything but this is the approach I used, present in the initial question, I did self.write and then used a client action but the field value is not updated in the UI only after refreshing the form view.

To achieve the desired behavior where the field value is updated and a notification is displayed without needing to reload the form view, you can use a combination of client-side and server-side actions. Here's how you can do it:

1. Update the field value on the server-side using self.write() as you are currently doing.
2. Send a client-side action to update the UI and display the notification using JavaScript.

Here's an example implementation:

from odoo import models, api

class YourModel(models.Model):
    _name = 'your.model'

    @api.model
    def update_field_and_notify(self):
        # Update the field value
        self.write({'is_published': True})

        # Return client-side action to display notification
        return {
            'type': 'ir.actions.client',
            'tag': 'notification',
            'params': {
                'title': 'Success',
                'message': 'Agent was successfully updated',
                'sticky': False,
            }
        }

In your XML view, define the button to trigger the action:

    your.model.form
    your.model
   
       
           

This way, when the user clicks the button, the field value will be updated on the server-side, and a client-side action will be triggered to display the notification without needing to reload the form view. This provides a smoother user experience.