What's your goal? Why do you want to learn a "lower level" language? Do you have experience in "higher level" languages?
I would say that a better approach in your case is to start by saying "I want to write programs to solve problems like XXXX", or "I want to learn a language that lands me a job doing YYYY".
For example, if you want to:
- build network services -> golang
- fiddle with OS level stuff (schedulers, memory management, etc.) -> C
- write high performance calculation/simulation programs -> julia
- get a nice solid base that can cover most of the above and has a promising future -> rust
Nim, D, V, Zig are very niche and I wouldn't recommend as a first "lower level" language (because you'll have a harder time finding answers, and they won't give you clear benefits over the other options in any problem space).
C++ is... huge. Modern C++ is a fine language, but you'll have to learn a lot to be able to handle it.