Massive problems getting the PC software running on openSUSE Leap 15.5

[azalanono]

Hello.
I wanted to do first steps with my "tinySA Ultra" and the python software I downloaded from github.

The problems start very early, for sure some module is missing. But I am not familiar with python at all.
System: openSUSE Leap 15.5, KDE5/Plasma desktop.

• I downloaded the complete software tree as ZIP.
• I created a directory ~/tinysa and stored this .zip file there, then I unpacked it. I got a directory "QtTinySA-main" with some more directories, one is "src".
• From a console I cd to ~/tinysa/QtTinySA-main/src , there I can find several .py programs, QtTinySA.py is executable.

When typing in the command 'python2 ./QtTinySA.py' I only get the following output:

python3 ./QtTinySA.py
Traceback (most recent call last):
File "./QtTinySA.py", line 33, in
import platformdirs
ModuleNotFoundError: No module named 'platformdirs'

I already installed a package with "platformdirs" in its name, in detail "python311-platformdirs", but I still get this error!

It would be very kind if somebody can guide me. I don't want to damage my PC setup.