Marginalised posterior distributions of the cosmological and nuisance sampling parameters inferred from the combination of KiDS-Legacy with DESI DR2 BAO, eBOSS DR16 RSD, and Planck 2018 TTTEEE, low-ℓ TT, and low-ℓ EE datasets. The black contour shows constraints from a ΛCDM analysis. The blue, green, and orange contours illustrate the resulting posterior from modified gravity analyses using the stable parameter basis of ${\widehat{D}}_{\mathrm{kin}}$ and $\mathrm{\Delta }{\widehat{M}}_{\ast }^2$, the stable parameter basis of ${\widehat{D}}_{\mathrm{kin}}$ and ${\widehat{c}}_{\mathrm{s}}^2$, and the α_B-α_M parametrisation, respectively. The inner and outer contours of the marginalised posteriors correspond to the 68% and 95% credible intervals, respectively. The list of top-hat priors for these parameters is provided in Table 1.