Broadly agreed, the concurrent Go code I've gotten out of them has been absolutely riddled with issues, and they're even worse at writing tests for it. They can get tutorial-level code on the first shot almost always... but tutorial-level Go code is often rather unusable in production due to missing error handling or observability.
Go's generics are getting a fairly important improvement soon though! Generic methods, finally! It should help open up some more ergonomic patterns: https://tip.golang.org/doc/go1.27