Thin lines with different colours: simulated VSFs for 50 random LOSs, with an area of 90 × 90 kpc², randomly extracted from our two-dimensional velocity map and with separations as in the XRISM observation of Coma. Blue lines: Full three-dimensional VSF for the velocity along the LOS component, using 10⁷ cells in the cluster volume. The grey points are the XRISM measurements for Coma. The additional dashed lines show the best-fit models derived Xrism Collaboration (2025b) for a Kolmogorov spectrum (red) or a much steeper one (green), while the shaded grey area shows the 68% cosmic variance uncertainty and the measurement statistical errors in the same work.