Alert questions(frequency of state changes, send [ok] only when problem solved)

Good afternoon,
I encountered an inconvenience in which for CollectD Server Metrics / Disk Usage we receive email notifications when the state changes: alert (which is correct in most casses), and ok (incorrect, since the state is still alert). In addition to the ability to completely disable the [ok] notification in notification channels, is it possible to send it only once when the problem is actually solved?
Also, the regularity of the frequency of sending alert notifications is not entirely clear (for example, from 15:00 to 15:30, the frequency of state changes is higher than from 14:00 to 14:30). What functionality regulates it?
Last but not least : Considering that the utilization of space on the server was more than 90% since the night, why did the alerts start coming only after 14:00

  • What is your Grafana version?
    Grafana v8.0.3
  • Are you using Grafana Cloud or self-hosted Grafana?
    I believe its self-hosted Grafana
  • Are you using legacy alerting or Unified Alerting?
    I believe its Unified Alerting
  • was the alert in question migrated from the legacy platform into Unified Alerting, or did you first create it inside the new platform?
    Not sure