With your example, it was printing 2 rows and 1 column for me. Try putting the QRangeModel now into a TableView or TreeView's model. You can see that the data is weirdly smushed into that one column.

I don't think it will be wrong for me as mine reports 4 columns where yours reports 1. Your problem for that is at the model side, for whatever reason. My suggestion is that this is working "oddly" in PySide6 and explicitly rejected in PyQt6, so all bets are off. And we don't know what platform/Qt/PySide/Python version you are using, may be different from mine.

import sys
from PySide6.QtCore import QCoreApplication, QRangeModel
#from PyQt6.QtCore import QCoreApplication, QRangeModel

if __name__ == '__main__':
    app = QCoreApplication(sys.argv)
    table = [
        ["foo", "bar", "rab", "oof"],
        ["hi", "bye", "eyb", "ih"],
        #[1, 2, 3, 4],
        #[5, 6, 7, 8],
    ]
    m = QRangeModel(table)
    print(m.rowCount(), m.columnCount())
    print(m.data(m.index(0, 0)))
    print(m.data(m.index(1, 0)))
    # sys.exit(app.exec_())

Firstly: I do not get your

Getting the data shows that it has created: fbro and hbei as the two items in the one column. It pulled the first character from each string, and created a new one from it.

Instead I get a single column with the full list ["foo", "bar", "rab", "oof"] in it. As I would expect. With the number lists instead I do get 4 columns. Maybe something to do with QStringList being a known type/QVariant-convertible while QList<int> is not?

However, in any case I do not see how your lists-as-elements make any sense for your attempted use of QRangeModel here? Tellingly, if I change to use PyQt6 instead of PySide6 both string-list and number-list cases generated error:

TypeError: QRangeModel(range: QPyAbstractRange|None, parent: QObject|None = None): argument 1 has unexpected type 'list'

So no code with list-elements is acceptable as a QRangeModel to PyQt, which is actually what I would expect, I think (not quite sure how QRangeModel is supposed to be used).

The fact that PyQt rejects this attempt while PySide accepts it but then behaves oddly "sounds an alarm bell".

You may need to explain exactly what you are trying to achieve with these "range-models-of-list-elements".

It is possible that a new class introduced apparently at Qt 6.11, QRangeModelAdapter Class, may be relevant to you. Googling delivers:

QRangeModelAdapter is a component introduced as a technology preview in Qt 6.11 designed to simplify how you modify data structures linked to a QRangeModel. It provides a bridge that allows you to interact directly with an underlying sequential data structure (like a Python list or a NumPy array) using standard, convenient methods without manually dealing with boilerplate QAbstractItemModel conventions, QModelIndex tracking, or QVariant wrapping

Behaviour is all tied up with C++ ranges, I don't know whether that may have a problem from Python.