Diagnostic diagrams based on the best preferred line ratios using the ch3-all cubes, on a logarithmic scale (see Fig. 4 and details in Sect. 3.3). Each point is a cluster from the galaxies used as the training sample, colour-coded by their assigned class probability (AGN in orange, SF in green, and Other in blue; see details in Sect. 3.3), with darker colours indicating a higher probability. The initial training labels of the clusters (see Table B.1) were obtained from previous detailed JWST MIRI/MRS analysis of the sources (see references in Table 1, and details in Sect. 2.3). Contours show the kernel density estimate (KDE) of the distribution for each class at four probability levels: 0.5, 0.6, 0.75, and 0.9.