I discovered that ctrl-c will go to normal mode, which is apparently rare but is an easy one-hand solution without moving your hand as far (and it doesn't need any config).
I think you can however `inoremap <C-c> <esc>` locally to make it a bit safer, and just use the default Ctrl-C remotely (if your vimrc is not there then there’s probably no plugins or abbreviations to worry about).