> Reading new books on unfamiliar subjects, practicing intensely for months to develop a new skill, talking with an expert and absorbing decades of wisdom as they share a lifetime of experience.
Honestly, these are wildly different forms of "learning" and you're unlikely to find a community engaged in all three.
Tons of book clubs exist if you just want to talk about the latest Malcom Gladwell book. Or discuss whatever pop-sci flavor of the month shows up on TED recently. Over time I've become a bit disillusioned with this form as learning because authors tend to both simplify reality, and overstate the reliability of research findings. Sometimes its not exactly their fault when science is retracted but it suggests that focusing on "new" is less useful. When I realize I've forgotten most of what I've read, it makes me feel slightly less anxious about how wrong much of it was.
For skill acquisition, affinity communities on the skill: juggling, knitting, cycling, language, art, chess, sports all have clubs and similar. These tend to focus on continual honing of expertise in the area, instead of acquiring a skill and moving on to another.
For learning from experts, well, conferences and symposiums abound. And again, they cluster around topic instead of mode of learning. Conferences are usually about publishing new findings and pushing the frontier of the unknown forward but its a much harder, slower and difficult task than learning settled science from a textbook. You can learn about astrophysics without knowing what a z-score is but its definitely something to be aware of when attempting to convince the expert community of a new fact.
MasterClasses are often kind of an interview format you may enjoy, and if you seek in person formats, sometimes colleges and museums hold public seminars, and some day soon may resume.