Out_file short flush interval with timekey 1h in buffer

[hoooli]

'm trying to eliminate the forest plugin that I used before for dynamically generating paths for file output. I need to have files in the format app.2024020813-0.log, where '0' represents the worker_id. Currently, end of my configuration that works is:

<match **> #tag cluster.namespace.app
   @type file
   @id "save-#{worker_id}"
   path "fluentd/log/${path_cluster}/${path_namespace}/${path_app}/${path_app}.*-#{worker_id}.log"
   append true
   <buffer path_cluster,path_namespace,path_app,time>
      @type file
      timekey 1h
      flush_mode interval
      flush_interval 3s
      flush_at_shutdown true
   </buffer>
      <format>
       @type single_value
       message_key log
      </format>
  </match>

But because of the 1h timekey the flush interval is ignored - it takes really long time to flush the buffer to the logfile. How can I change the setting to flush every 3s (I want to see actual logs) and have the file in format "app.%Y%m%d%H-#{worker_id}.log"? I tried time_slice_format and time_format, but the output file format needs the timekey (without timekey the dateformat has incorrect hours - it looks like 2024020800-0 even at 11am). Is there any workaround?

My FluentD version is 1.16.3-2.0

Thank you