In this paper, our focus is on a specific class of non-linear $\psi$-Hilfer fractional generalized double phase-Choquard differential equations involving the $p$-Laplacian operator with Dirichlet boundary conditions. The equation is given by: \begin{equation*} \begin{cases} \mathcal{L}^{\gamma,\beta;si}u=eft(\displaystyle ıt_{mega} \frac{G\big(u(x)\big) }{|x-y|^{ambda}} dx \right)g\big(u(y)\big),& \mbox{in}\;{mega} , u=0, & \mbox{on}\; tial mega, \end{cases} \end{equation*} with $\mathcal{L}^{\gamma,\beta;\psi}$ is defined as: $$\mathcal{L}^{\gamma,\beta;si}u:= \mathbb{D}_{T}^{\gamma,\beta;si}\Big(|\mathbb{D}_{0^+}^{\gamma,\beta;si}u|^{p-2} \mathbb{D}_{0^+}^{\gamma,\beta;si}u+\mathbf{a}(x)|\mathbb{D}_{0^+}^{\gamma,\beta;si}u|^{q-2} \mathbb{D}_{0^+}^{\gamma,\beta;si}u\Big),$$ where $\mathbb{D}_{T}^{\gamma,\beta;\psi}$ and $\mathbb{D}_{0^{+}}^{\gamma,\beta;\psi }$ are $\psi$-Hilfer fractional derivatives of order $\frac{1}{p}<\gamma<1$ and type $0\leq\beta\leq1$ and $\mathbf{a}(\cdot)$ is non-negative weight function, and $G(\cdot)$ represents Choquard nonlinearities satisfying a certain growth conditions. By employing the mountain pass theorem without the Palais-Smale condition, along with the Hardy-Littlewood-Sobolev inequality, we establish the existence of a weak solution to the aforementioned problem. Our main results are novel and contribute to the literature on problems involving $\psi$-Hilfer derivatives with the $p$-Laplacian operator. This investigation enhances the scope of understanding in this specific class of problems.