  We explore some cosmological features of the newly suggested 4D Gauss-Bonnet
gravity through two different models assuming a varying cosmological constant.
Observational constraints, such as the cosmic transit and the flat curvature,
have been considered in constructing the models. The cosmology in the current
work has been probed using a given scale factor derived from the desired cosmic
behavior which is the inverse of the usual viewpoint. The stability and
cosmography have been studied for the two models.
