Intrinsic spin–orbit interaction in germanium provides electrically active flopping-mode qubits without requiring magnetic-field gradients to generate spin–charge hybridization. We study double quantum dots (DQDs) with a multiband Luttinger–Kohn framework that retains heavy-hole (HH) and light-hole (LH) states on equal footing. Modeling vertical confinement with a finite confinement potential along the growth direction brings selected subbands into a regime of appreciable HH–LH mixing. This admixture activates electric-dipole spin-coupling through LH–LH and LH–HH transitions, complementing the conventional HH–HH pseudospin-flip resonance. For the parameter sets considered, these additional channels can produce larger spin–photon figures of merit than the HH–HH transition. HH–LH mixing thus supplies a tunable ingredient for qubit–cavity coupling in germanium hole-spin qubits and extends the operating regimes available to circuit-QED architectures.