Bifurcation and multiplicity results for critical Grushin-Choquard problems

We consider the following nonlocal Brézis-Nirenberg type critical Choquard problem involving the Grushin operator \begin{equation*} \left\{ \begin{aligned} -Δ_γ& u =λu + \left(\displaystyle\int_Ω\frac{|u(w)|^{2^*_{γ,μ}}}{d(z-w)^μ}dw\right) |u|^{2^*_{γ,μ}-2}u \quad &&\text{in} \ Ω, u &= 0 \