Try Aurora 4x http://aurora2.pentarch.org/index.php . It's probably the closest to "real" and "fun" as you can get. Not that detailed as you speak, but as already mentioned by others - in reality, space is really really big and really really boring.
Even though it's "old", but back in July (2020) we could replicate this behavior.
One main aspect of "why" we are swithcing to rust is that our project needs to handle large amounts of data (think > 15Gb in RAM). When you try to work with large data structures within RAM, the GC of golang goes a little nuts. There's many different memory issues that we found, for example, when we put a larger load on our project, there's allocations happening, but Golang won't deallocate or release the memory to the OS unless the load goes down.
But if you don't have to work with large data structures and need a speedy multithreaded solution, then you can definately go with golang.
I would also like to point out that it's not very accurate to say that Rust has moderate C++ flavor. It has C flavor with some "differences" when it comes to variables and their lifetimes as well as some different minor flavors of other languages. For example, it has channels, which work in a very similar way as in golang. It has stream (functional) programming to be done as easy as with Java.
The biggest issue with Rust is that there's no well established libraries to work with and sometimes you get major incompatibilities or the issue when you have to so many different 3rd party libraries, that it becomes unconfortable to manage.
I would disagree with the second part of your statement where trying to do completely different jobs will lead to poor performance. It is indeed a double edged sword, however the real world (languages, frameworks, libraries, technologies, trends) change extremely quickly. Having the ability to react and adapt by understanding programming abstractions and fundamentals will help you rather than lead to poor performance.
On the other hand, being focused would make you a niche specialist, which in these days is a thing hard to find. One must be careful not to learn something that might be gone tomorrow. I doubt there is a big need for lua or erlang developers these days. You can be the best, but if you are not needed, this could be simply depressing rather than useful.