The fix is to either run the 'sudo install-picochess.sh pico' command or the command suggested in the ERROR 'sudo setcap 'cap_net_bind_service=+ep' $(readlink -f $(which python3))'.
And as you don't want to run install-picochess.sh which updates to the latest picochess you need to run the second command: sudo setcap 'cap_net_bind_service=+ep' $(readlink -f $(which python3))
I would not recommend replacing, editing or moving around any python files as they change heavily all the time. Up until now the rule has been that if you run sudo apt upgrade you do need to run install-picochess.sh command, and its faster with the parameter pico. If I would to create a branch for Antonios special version you could actually run install-picochess inside it as picochess would only update to the latest of that branch, but I need to get the code for it in order to do so.
And yes, please let us know what we still need to fix in the latest version. The new 3x3 tile system menu is a quite much larger menu now as of the 4.3.1 latest release in the weekend. But do let us know whats stopping you from upgrading. Maybe we can fix it.
-- Johan