We compute the renormalized scalar vacuum polarization $\phisq$ of a massive, non-minimally coupled quantum field in the Hartle–Hawking state exterior to a family of static, spherically symmetric , and black holes: the Kazakov–Solodukhin (KS) quantum-deformed black hole, the two effective loop-quantum-gravity geometries of Zhang–Lewandowski–Ma–Yang (ZLMY-1 and ZLMY-2), the renormalization-group (RG) improved Schwarzschild black hole of Bonanno–Reuter (BR), and the Bardeen regular black hole. We adapt the extended point-splitting formalism, implemented as a high-performance code, and present the exterior profile $\vp\equiv16\pi^2M^2\phisq$ over a grid of the quantum-deformation parameter, the field mass $\mu =mM$ and the curvature coupling $\xi$. KS the near-horizon polarization, while the four geometries with negative horizon Ricci scalar it. Measured against the horizon curvature $M^2\mr_{\rm H}$ – a measure of the deformation with the same meaning in every theory – the $\xi$-dependent part of the response, set by the DeWitt–Schwinger term linear in $(\xi-1/6)\mr$, is common to all five geometries to within $\pm 20\%$ at light field mass, and at equal curvature the total responses of ZLMY-1, BR and Bardeen agree to within a factor $1.5$; a further, $\xi$-independent part set by the horizon data is geometry specific. We verify the curvature mechanism both in magnitude and in the $\xi$-dependence. In the near-extremal regime of the two geometries with inner horizons we find a sign change of the horizon polarization at light field mass, appearing only once the horizon Ricci scalar has turned positive, removed by conformal coupling, and not found for Reissner–Nordstr"om ($\mr=0$) at matched temperature or matched horizon separation in the range probed, which identifies it as the DeWitt–Schwinger response to a positive horizon curvature. Every result reduces to the Schwarzschild value in the classical limit, validating the calculation. These constitute, to our knowledge, the first determinations of $\phisq$ for the KS, ZLMY, BR and Bardeen black hole geometries, providing a quantitative measure of quantum-field activity on these effective backgrounds.