I’d like to add to what others have said, the specific behavior of Ctrl+C on Windows and Linux is that it does nothing in normal mode, and in insert mode it exits back to normal mode without copying to the system clipboard.
Even with the unmap <C-c> fix, copying is fixed in normal mode but in insert mode it still exits to normal mode without copying.
As an alternative (or addition) to unmap <C-c>, one can set clipboard=unnamed to yank to system clipboard. It still requires the obsidian-vimrc plugin.