In this work, we investigate a spatially homogeneous and anisotropic BT-Formula: see text cosmological model filled with a perfect fluid source in the framework of modified Formula: see text gravity. Exact solutions of the nonlinear field equations are obtained by assuming a power-law relation between Formula: see text and the average scale factor together with a proportionality condition between the shear and expansion scalars. The obtained model describes a continuously expanding Universe with positive energy density, negative pressure, and a negative deceleration parameter, supporting late-time accelerated expansion. The EoS parameter remains entirely in the phantom region Formula: see text, while the Formula: see text phase-plane analysis exhibits attractor-like behavior. Energy condition analysis shows that the DEC is satisfied, whereas the NEC and SEC are violated, consequently, NEC violation is a sign of exotic phantom behavior arising from modified Formula: see text gravity effects, while accelerated expansion results from SEC violation. Perturbative analysis indicates unstable behavior under small fluctuations. Furthermore, observational diagnostics including Hubble evolution, distance modulus show consistency with DA, BAO, Formula: see textCDM, and Pantheon datasets. Therefore, the obtained BT-Formula: see text framework provides an observationally viable description of late-time accelerated expansion in anisotropic modified gravity cosmology.
Chinnappalanaidu et al. (Fri,) studied this question.