Task Tracker Tutorial with multiple projects and offline functionality

Hello I have a few questions on how to upgrade the Task Tracker in the tutorial.

If I were to add multiple projects to the Task Tracker I’ll need to make:
-A new collection of projects
-Each project will have a unique partition key
-Update the functions/custom user data to use the new project collection

For it to work offline with all the data available does that mean I need a realm constantly open for every project? At the moment the Task realm is only open and synced once a user clicks on a project while online. What I want is if a user opens the app while online and views the list of projects every project task is synced, so that when they go offline they can click on any project and see the updated tasks. Also if they add a bunch of tasks to different projects while offline they shouldn’t need to open every project while online for the tasks to sync.

Is it bad having multiple realms open at once? Each open realm on the device counts as a Concurrent Listening Client on https://docs.mongodb.com/realm/reference/service-limitations/ right? So if there’s one user with 250 projects syncing that uses up the entire limit for the Free Tier?

If having multiple realms open at once is bad what’s the solution?
Do I cycle through all the projects and open and close a realm for each project on a timer?
Do I make a new collection and aggregate all the tasks/projects for a user on one partition key so it all syncs down together for a user and make the appropriate realm functions to handle updates for it?

Thanks for your time!