I like create a new step for clickhouse database incredible.
It is actually quite easy to create your own PDI steps, if you are familiar with Java. I myself created some custom steps for the company I work for. I learned the most by looking at the implementation of steps available in Pentaho on Github.
Other good resources are;
Create Step Plugins - Pentaho Documentation
Building Step Plugins with PDI / Pentaho Kettle | Codeks Blog
Exploring the sample plugins for PDI | Adventures with Open Source BI
I hope this helps you get going
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