Realm Flexible Sync - limit on the array length in the query

MongoDB Atlas App Services & Realm
1

I need to sync one collection named “Employee” using Flexible sync and the flexible sync query field is employeeId (Employee.employeeId).
My subscription would be something like: employeeId in Array[employeeId]

Questions:

  1. is there a limit on the array length [employeeId]?
  2. If not limit, does it have any performance issue if the array length is more than 1000.