Non destructive way of clearing all indices

Elastic Stack Elasticsearch
1

I have been using:

curl -X DELETE "https://localhost:9200/_all

to delete all indices. I am doing this in a kubernetes ECK environment. It seems to break things though and kibana pod gets into trouble. Am I right in saying that I shouldn't delete the .kibana index?

2

Ideally nothing starting with a . as it would be considered a system index.