Adding a bit of C to your tool belt will give you success wherever you go. The concepts it teaches are invaluable in understanding why things are built the way they are today. Everything from memory management, to trying to solve all these vulnerabilities, to why new languages have these crazy constructs.
Unlike Rust, Nim has far fewer learning resources (tutorials, books, courses) which may or not be important to you.
Recently I've been coming across ML family of languages. I see compiler books in OCaml. Atleast in the academic discussions I see the need to get away from C in terms of building reliable computer systems. Maybe it's a bit of a stretch to call it a systems programming language but maybe something to consider.
A language like Java or C# is perfectly fine for "systems" tasks such as compilers, database engines, etc. You don't need to interact with memory on a low level and you can afford to pay the cost of automated memory management for some guarantee that you don't get use-after-free and similar problems.
For that matter if performance doesn't matter you can do a lot in Python, Javascript, and other languages that people think of as "applications" languages.
For some other "systems" tasks, such as embedded, you are going to have a choice between C/C--, Assembly and maybe Ada or a Pascal variant if you're adventurous. In that case you need absolute control over memory layout. C has the particular advantage of portability. I think it's an atrocious language to program the AVR-8 arduino but your code is portable to a more powerful board and your skills are portable.
Rust has the "borrowing" model that is potentially more efficient than the garbage collection model of languages like Java and gives you some control over the layout. You might like it or you might learn to hate fighting with the borrow checker.
What domain you are in absolutely determines what languages you can use.
Python- it has a very simple syntax and it’s easy to learn. It can be used for modular programming and object oriented and it is forgiving if you don’t strictly follow the best practices. Therefore it can help to make thing working while you’re learning
I think C is pretty friendly as long as you can get through the basics of arrays and pointers. It's friendly in the sense that there is not a lot of grammar to learn.
But each field of system programming requires a deep understanding of something other than the language itself so overall I'd say it's difficult to get in.
Personally I tend to use it for light one-off database metaprogramming. Get a lit of objects that need to be maintenanced, generate the appropriate commands with a column of identical formulas, and then paste that back into the sql utility. (For more complex or long-lived things I'll use a more traditional language of course.)
(Why yes, I am going to pretend I didn't accidentally a word.)