The shebang seems underbaked to me.  There is no way to reference a user's home directory AFIK.  I came across this annoyance when trying to make my python virtual environment portable.
 replies(2): 
You can use env[0] to invoke a command based on `$PATH` if desired:
  The env utility uses the PATH environment variable to 
  locate the requested utility if the name contains no `/' 
  characters, unless the -P option has been specified.
0 - https://man.freebsd.org/cgi/man.cgi?query=env&apropos=0&sekt...