Why the service --status-all is not listing this working service?

Solution 1:

According to the manpage

service --status-all

shows

service --status-all runs all init scripts, in alphabetical order,
with the status command. The status is [ + ] for running services,
[ - ] for stopped services and [ ? ] for services without a
status command.  This option only calls  status for sysvinit jobs.

ls -al /etc/init.d/

There can you see the listed services from sysvinit system.

You wrote an systemd unit, they can be listed with:

systemctl list-units     # for currently active units
systemctl -a list-units  # for all known units

Add the --user flag to these commands if you want to list the current user’s units instead of the system ones.