Messaging using internet data using default phone apps, reduce cost

Hi Partners

Good day

We have clients who constantly use the SMS service on the platform, the common use case is a manager send one-way messages with hundreds of more drivers or phone users on the field

This works well, however as you could imagine these could incur huge SMS cost over time. Has anyone encountered a way to send messages using data connectivity, without the use of third-party apps, with the default phone apps (e.g., iMessage on the apple, Message on the android) since installing the additional app will also potentially incur the cost

Having this feature would greatly reduce operating cost, up to thousands of dollars per month depending on volume, for fleet managers and clients.