Hi,

You can create a server action to execute the register_all_pricelists method on the pos.config model. To do this, go to Settings -> Technical -> Automation -> Server Actions and create a new action. In the "Action To Do" tab, set the "Model Name" to pos.config and the "Action Type" to Python Code. In the "Python Code" field, paste the code below. 

def register_all_pricelists(self):
        # Get all pricelists
        pricelists = self.env['product.pricelist'].search([])
 
        # Get POS configurations
        pos_configs = self.env['pos.config'].search([])
 
        # Register all pricelists in POS configurations
        for pos_config in pos_configs:
            pricelist_ids = [(4, pricelist.id) for pricelist in pricelists]
            pos_config.write({'pricelist_ids': pricelist_ids})
 
        return True

Regards