How to contribute to open source data stores?

I've been a software engineer for 15 years, mostly java and scala. I tried reaching out to the datastax/cassandra folks a few times in my career and didn't receive any guidance on how to start helping out. I've done some small contributions with the hadoop ecosystem, but it's mostly mature/slowly moving these days.

I've wanted to contribute to questDb, but it just seemed a little daunting. is there any easier way to start contributing (not documentation/testing) in the java db community? I'm happy at my job and not looking to use this as a foot in the door, I would simply like to be more involved in something interesting and low latency related in the java community. (also open to other projects!)