@Martian2020: All control characters are offset from the corresponding letter by decimal 64 (hex 40). See this page: en.wikipedia.org/wiki/Control_character. Note that it uses another common representation: ^J. See also en.wikipedia.org/wiki/C0_and_C1_control_codes#ASCII where ^J, "Line Feed" and "end-of-line" are used.

@Martian2020: man ascii will show that C-j is newline and C-m is CR (return). These are basic well-known, well-defined characters that should never be remapped.

@Martian2020: C-j is bound to the Readline function accept-line as is C-m. You can find aacept-line in man bash. By the way, C-j is newline and C-m is carriage return.

@SimonRichter: If by "actively suggest" you mean command completion, it only functions if the file is marked executable.

@MatthaeusGaiusCaesar: That may be true for some, but the OP specified not to touch single spaces and my answer clearly states this condition. To convert all spaces to tabs I think it's as simple as removing the space after the plus sign in my commands.