The best way to do it (if you can) is to get paid for making the change.

First, study C and/or Rust on your own. Maybe do a personal project or two.

Second, find something at work where Rust or C would bring some benefits. Tell your boss that you think this would work better in a language like Rust or C, and explain why. Volunteer to try to do it. (Note: Appearing too eager at this point might be a mistake.)

Do the second step a few times and you become the Rust/C expert. And you get paid as you do the work that helps you get better!