I agree with HJarausch. Among new system languages NIM has extraordinary
potential because is smart and flexible, without be intimidating as other ones.
Also it has very fast compile time and produce small binary files that is a
huge benefit. You may also think to write your own superfast Python module (NIM
compiles to C) using nimpy/nimporter. RUST benefits from an incredible backup
from big companies... it's powerful, no doubt, but it's really unpleasant to
read (this of course is my personal opinion) and might prove to be as complex
as C++. Anyway learning more than one programming language will teach a lots of
things, so you might consider to pick more than ones. E.g. I believe that
having some grasp on C will always be worth the effort, because it will stay
around for a lot of time, and you may encounter it e.g. if you dig a bit on
Linux or you want to snoop on high performance Python libraries. You may think
of C a bit like the "modern" Assembler (but much more approachable). If
starting today, I probably would not start the long C++ journey.