Curious if there’s a reason Java/Kotlin wouldn’t have worked? There are a number of fast, statically typed languages with much less developer overhead than C++.
Do any of them have comprehensive standard libraries, and compile to small native binaries? Those features, along with performance and support for parallelism, are why I chose Go (for command-line apps).
Small native binaries don't seem like much of an advantage when writing servers. For command-line apps sure, but it sounds like OP was addressing someone who was writing a server application.
With GraalVM you can compile JVM languages to small executables with limited memory consumption. It's fairly new technology but people are using it in production.
Java can be as fast as Go if you are careful. Unfortunately idiomatic Java isn't terribly fast because of the pointer chasing behaviour in its collections. The only way to avoid the issue is to work primarily with arrays of basic numeric types. If you sort a large vector<Point3d> in C++ it will be an order of magnitude faster than sorting a similar looking ArrayList<Point3d> on Java because the C++ version stores and allocates these tiny objects in a contiguous memory block.