A big part of the problem is just the instability of the API.
If it was more stable, it would be possible to use e.g. stackoverflow to build a base of solutions to common problems, a canonical way of doing things, but since gradle keeps shifting and changing with every other release, that really isn't possible.
You can search "how to do X Gradle" and come away with a dozen implementations. There often seems to be at least 3 different APIs to accomplish a simple task, one ancient that's deprecated but kept around for compatibility reasons, one "new' that the Gradle devs later decided was bad, and then the proper "new" one which doesn't have all the features that people needed.
If it was more stable, it would be possible to use e.g. stackoverflow to build a base of solutions to common problems, a canonical way of doing things, but since gradle keeps shifting and changing with every other release, that really isn't possible.