Asking for help creating an in-queue flow with a wait action set to 30 seconds, then a collect input action that asks the customer if they wish to wait in the queue or they would like to receive a chat link, then a decision action which based on the input ether continues with the execution of the flow or initiates a custom data action that sends the URL
The data-action should be something that can send an SMS to the customers phone, with the URL of the chat you want the customer to start. This would need the API endpoint of the SMS application.