Is subsync only using one cpu core?

[Angel Siles Ruf]

Hello everybody.
In advance, thanks for your hard work.

I have installed subsync with a bazarr docker environment.
All is working correctly, but the sincronitzation is really slow...

I noticed subsync only use 1 thread of 8.
If i execute more than one subsync command, happens the same but now the docker container use 2 cores.

The command im executing is:

/usr/bin/python3 /usr/bin/subsync --cli sync --sub-lang spa --ref-lang eng --sub /library/Movies/THEMOVIENAME.es.srt --ref /library/Movies/THEMOVIENAME.mkv --out /library/Movies/THEMOVIENAME.es.srt --overwrite --jobs 8 --effort 1

YELLOW MARK IS CPU USAGE -->

Thank you.

EDIT: Maybe the problem is PYTHON3?