By definition, monetization model means … is how you get from “not collecting money” to “collecting money”:

Base on your description, will this be too early as the MVP is not yet out and we don't have subscribers. We can design a monetization model when you have a reasonable size of free subscribers.

If you wanted to test whether your MVP can fetch some income, you should charge a subscription on your MVP to see people want to use it or not. Here we refer to this as designing the revenue model. - I believe you are at this stage.

The monetization model and revenue model are different strategies we should avoid using them loosely.

If you need help, please feel free to contact me