  The current paper provides a comprehensive examination of a dark energy
cosmological model in the classical regime, in which a generic scalar field is
regarded as a dark energy source. Einstein's field equations are solved in
model independent way i.e. using a scheme of cosmological parametrization. A
parametrization of the density parameter as a function of the cosmic scale
factor has been investigated in this line. The result is noteworthy because it
shows a smooth transition from a decelerating to an accelerating phase in the
recent past. The model parameters involved in the functional form of the
parametrization approach utilized here were constrained using certain external
datasets. The updated Hubble datasets containing 57 datapoints, 1048 points of
recently compiled Pantheon datasets, and also the Baryon Acoustic Oscillation
(BAO) datasets are used here to determine the best-fitting model parameter
values. The expressions of several significant cosmological parameters are
represented as a function of redshift `$z$' and illustrated visually for the
best fit values of the model parameters to better comprehend cosmic evolution.
The obtained model is also compared with the $\Lambda CDM$ model. Our model has
a distinct behavior in future and shown a big crunch type collapse. The best
fit values of the model parameters are also used to compute the current values
of several physical and geometrical parameters, as well as phase transition
redshift. To examine the nature of dark energy, certain cosmological tests and
diagnostic analyses are done on the derived model.
