Another neat trick is to use ctrl-x ctrl-e, this gets the command in a vim buffer (default editor for me). Edit the command and then :wq to reflect the changes
As someone who is currently learning Rust, which is lower level than Java (used at work).
Having studied C and using some portion of C++ at university has been immensely helpful.
I would recommend learning C, as it is a relatively small language; and focusing on understanding the underlying assembly which is generated by the compilers. (Compiler Explorer gotbolt.org)
You can also refer to Stanford CS107 lectures taught be Jerry Cain when you are somewhat comfortable with C.