Ground states for $p$-fractional Choquard-type equations with critical local nonlinearity and doubly critical nonlocality

We consider a $p$-fractional Choquard-type equation \[ (-\Delta)_p^s u+a|u|^{p-2}u=b(K\ast F(u))F'(u)+\varepsilon_g |u|^{p_g-2}u \quad\text{in $\mathbb{R}^N$}, \] where $0