UmfPack solver and multithreading

[ioannisVM]

Hello!
I run Ubuntu 20.04 on two machines. I am running an analysis using OpenSeesPy that uses the UmfPack solver.
On one machine, htop shows that it is using all of the four cores that it has.
My new machine has 12 cores, but unfortunately when I run the same script it only utilizes a single core.
I don't know much about what factors influence this behavior. Could it be libraries that I had apt-installed on my old machine to compile OpenSees, or does that not affect OpenSeesPy? How can I make it so that UmfPack uses all the cores on my new machine?
In both workstations I installed OpenSeesPy through pip, and I am managing enviornments using conda.
Let me know if you need any specific details, and I appreciate your help!

[ioannisVM]

I would really appreciate it if someone could give me a starting point on this. I still haven't resolved this issue.