The launcher completely overrides log4j configuration file even if -Dlog4j.configurationFile property is passed. This probably should not happen.
Possible solution is creating a new profile and removing 'logging' section, which downloads log4j configuration file.
Or as an alternative please add an option to enable debugging mode, configurations may be found on https://wiki.vg/Debugging
This issue seems to describe the same problem as MCL-17489, which was resolved as Won't Fix a few months ago.