In my case, using Py_SetPythonHome() causes conflicts and I am not able to import the libraries from my virtual environment. What I did was to remove Py_SetPythonHome() and point the PYTHONPATH environment variable to the site-packages inside my virtual environment before calling Py_Initialize(). In short:

QString python_path = "PATH_TO_ENVIRONMENT/lib/python3.11/site-packages";
setenv("PYTHONPATH", python_path.toStdString().c_str(), 1);

Py_Initialize();
if (!Py_IsInitialized())
{
  qDebug() << "Failed to initialize Python interpreter.";
  return;
}
PyRun_SimpleString("import numpy"); // import modules from my venv
Py_Finalize();