Java ecosystem overview for experienced programmers?

Seems like a strange question to ask, but ... I've worked with C++ (with bouts of Python and Go) most of my life, and am part of a "mostly Java" tech stack right now. Given that I'd never used IntelliJ before, and never knew what 'Maven' was, I'm ... reasonably productive, but how can I "ramp myself up better" ?

There is obviously reams of beginner texts, and useful performance-oriented texts, but is there any sort of "general ecosystem" guide? (best practices around packaging, tooling, that sort of thing?)

A note while I'm here: I was surprised to find that Java today is totally different from when I formed my first (late 90s, as 'applets'), second (early 2000s, part of some university projects) and third (mid 2000s, TAing, more projects) impressions of it, and is actually (JVM for sure, but also increasingly the Java language itself) much more expressive, introspection-friendly, and productive than I thought.