Hello, please avoid bumping posts when less then 24 hours have passed
This may be your issue, HDD is bad for performance, not sure you will be able to improve this without changing to SSD.
You didn't answer that, I'm assuming you didn't change this setting.
Try increasing pipeline.batch.size in your logstash.yml or pipelines.yml, depends on where you are setting your pipeline.
The default value is 125, increase it and see if anything changes, like teste with 250, then 500.
You may need to restart logstash for the changes to work.
Also, did you check the documetation about tuning elasticsearch for indexing speed? There are some hints there of things that you may try to see if this improve.