Different access for users on different pricing tiers

Hi team -

What’s the best way to do the following?

Say I have an app with different modules, eg CRM, Accounting, HR software, where users can subscribe to each individually. These apps speak to each other eg comp from HR system feeds into the accounting system
I’d they pay for both modules.

What is the best way to toggle access on / off to modules based on whether users have subscribed to each model?

Any thoughts would be very appreciated

I am sure there are several ways to do it. From my little experience I can share that every module can act as a single page app.
Let’s say you have 4 modules so 4 pages can be built. Each page will act as single page app. I mean CRM page will have all the CRM functionalities within the page itself.
Then each page can have their own access conditions based on user’s role (plan, subscriptions etc.)