From Java to Go, and never back, for Go programs use much less memory, warn-up much faster, need much less code lines to implement and compile much faster. Beside happier developer experience, my App Engine apps also save much money by using Go.
With Go it feels like all you need is a dependency manager and maybe a Makefile for more complex builds.
Go tools are not intended to be a full build system, so for more complex builds, Makefiles are still needed.
There's an alternative to using Apache Groovy for writing Gradle config scripts: https://blog.gradle.org/kotlin-meets-gradle . If you also use Kotlin instead of Java for your software on the JVM then you can stick to one language for everything.