For power user stuff, I’d say xda-developers.com is really good. For instance since you mentioned adb, they have this guide: xda-developers.com/install-adb-windows-macos-linu… (and other adb guides they link to at the end).
For news and rumors you have a bunch of Android blogs but I think you could just take a look at this community here from time to time as news that’s interesting usually gets shared, while the noise mostly doesn’t.
And I guess just keep using the OS and ask questions here as soon as they pop up in your mind, there’s fundamentally nothing really complicated about Android especially as Google was recently trying to get iOS users into Android.
Also, since you’re planning to get a Pixel, might as well take a look at !googlepixel too 👀 (disclaimer: I’m one of its mods).