ES App added new option called allow_skew. Adding allow_skew will increase the performance.
Searches offset by allow_skew always run over their scheduled time ranges. For example, if a search that is scheduled to run over the past 5 minutes every 5 minutes is supposed to run at 2:05 p.m. but is offset such that it actually runs at 2:07 p.m., it will still search over 2:00:00 p.m. to 2:04:59 p.m.
Basically what it is saying is that there won't be any data missed, because it will still run in 5 mins interval, expect running at 5 min on the dot it will run after that. So even for critical alerts, it won't miss any data because it is still going over that time period, expect it's just starting a little later.
probably data model are still building, this will take time, depends on the size of your data, the configuration of data models, and other factors, you can go to a glass table, check ES health and see how many data models not completed yet, how many still building