Thanks to rbybbl and others before, I wrapped the knowledge into a Perl script (reconnect_6441.pl).
On most systems Perl is either readily available or it can be easily installed.

1. Place the code below into a file named reconnect_6441.pl and put it into any place you like.
2. Configure JD reconnects to do

   method: external batch
   interpreter: 'cmd /c' (e. g. on windows)
   script: perl -- .\reconnect_6441.pl <password hash>
   start in: <path to reconnect_6441.pl>
   

See the code comments to obtain your <password hash>.

https: //pastebin.com/0ctzg1FY