Existence and multiplicity results for a class of Kirchhoff-Choquard equations with a generalized sign-changing potential

In the present work we are concerned with the following Kirchhoff-Choquard-type equation $$-M(\mathrm{\mid }\mathrm{\mid }\mathrm{\nabla }u\mathrm{\mid }{\mathrm{\mid }}_2^2)\mathrm{\Delta }u+Q(x)u+\mu (V(\mathrm{\mid }\cdot \mathrm{\mid })\ast u^2)u=f(u)in{\mathbb{R}}^2,$$ for $M:\mathbb{R}\to \mathbb{R}$ given by $M(t)=a+bt$, $\mu >0$, $V$ a sign-changing and possible unbounded potential, $Q$ a continuous external potential and a nonlinearity $f$ with exponential critical growth. We prove existence and multiplicity of solutions in the nondegenerate case and guarantee the existence of solutions in the degenerate case.