Observed LF of M 83 (red line) compared to its Illustris-TNG50 analogs, with each analog corresponding to a gray line. The 1, 2, and 3σ confidence intervals are indicated with the green areas. The red numbers indicate the percentage of analogs that have more satellites than the observed one at a given step. Also shown is the Milky Way LF (blue), including (straight) and excluding (dashed) the rare Magellanic Clouds (MC). While the Milky Way LF without the MC is consistent with expectations from Illustris-TNG50, the M 83 LF deviates by more than 3σ.