The 5000 items issue is a SharePoint specific issue, no SP query can return more than 5000 items, it’s not specific to this activity package (you can try to create a view in a SharePoint site and you’ll see that it cant display anything if the filters return more than 5000 items, even if they are spread across multiple pages). The causes for this are related to the SQL database that SharePoint instances use to store their data.
To go around this issue, you need to retrieve the items using multiple queries, such that each query doesn’t exceed more than 5000 items. The way you decide to split the items into multiple queries depends on the usecase. One idea would be to use a query to return all items created between today and last 6 months, another query for the items from 6 months ago up to 1 year ago, etc…
But this won’t work until all the columns you need to use in the queries are indexed . See this for help with indexing: Add an index to a list or library column - SharePoint
Usually, if a list is already over 5000 items, you’ll need help from an admin to index the column, still, give it a try and see if you can do it yourself first.
I know this is very frustrating and it’s an issue I’ve struggled with in the past, but it’s 100% related to SharePoint itself, not the Activities Package