Does Apple provide any APIs that we can use to send blue imessages or sms on their sms app? Barring Apple Messages for Business? Or are all such APIs private and only choice is to rely on services like Twilio, Telnyx, LoopMessage, SendBlue etc?

I am trying to build a project. The service it provides is that it allows businesses to create configurable messages to send to users over iMessages, and receive their response and businesses can also set what response to send to each type of user response, receive payments and so on. It basically removes the headache of coding an automated chat based service for businesses by giving them a configurable platform where they can create such a service using simple UI.I'm not sure which APIs (iMessages APIs, Messages for Business APIs, or 3rd Party APIs) I have to use for my case. Now I looked up how something like this is possible. One thing I found was apple message for businesses APIs, as per my understanding of it, businesses can communicate using MSPs. But what I don't get is, are the businesses creating their own automated chat experience and MSP is just something that provides IT support as a security? Something like [Ntiva] has me guessing that line of thinking, but the documentation says MSP is supposed to provide messaging APIs, I don't see that on Ntiva. So if the MSP is supposed to provide APIs, then would my project be an MSP? I also checked out apple's iMessages APIs to send iMesssages, but as per my understanding, it can only be used if an extension is created by the developer and then downloaded by the user to add the specific chat automation, that is obviously not how businesses do it. Then I also found these 3rd party APIs that can send blue iMessages, like [loop message], [send blue] or [Telnyx]. So is my understanding that my project architecture should be an application that takes configuration from businesses, generates the respective messsage and then use Telnyx APIs to send those messages, receive their responses, make a response to it and use Telnyx APIs again and so on, correct? If so, what is the whole deal with messages for business thing? Is using third party APIs like loop message or telnyx a way to bypass those MSPs and stuff, or are these 3rd party party APIs taking care of the whole message for business and MSP stuff on their end and just provide us with the end APIs? I would really love to understand how this works, thank you so much