XDA forum was that for me. Great place to start and then follow links or do more research using the keywords used in the discussions. Just helpful for things like learning if a kernel is potentially fixable or not before buying a second-hand device for a custom rom project. The new look / reorganisation of stuff annoys me though as I find it harder to find stuff than it used to be but that’s because I am using it on autopilot. I guess new users might find it attractive / easy to navigate?