O–C diagrams of TOI-5624 e for two additional dynamical analyses to test the robustness of the five-planet solution. Left: Fit obtained from the TTV+RV analysis after adopting a broader prior on the orbital period of planet f (P_f ∈ [1,50] d), hence allowing configurations where the planet may lie between TOI-5624 d and e. Right: Fit obtained assuming again P_f ∈ [1,50] d, but using the transit mid-times only (i.e. excluding the RV dataset). Like the nominal analysis, both these analyses consistently conclude that only an external perturber may justify the TTVs of TOI-5624 e.