The radio-frequency (RF) performance of the p-type NiO-pocket based β-Ga₂O₃/black phosphorous heterostructure MOSFET has been evaluated. The key figure of merits (FOMs) for device performance evaluation include the transconductance (g_m) gate dependent intrinsic-capacitances (C_gd and C_gs), cutoff frequency (f_T), gain bandwidth (GBW) product and output-conductance (g_d). Similarly, power-gain (G_p), power added efficiency (PAE), and output power (P_OUT) are also investigated for large-signal continuous-wave (CW) RF performance evaluation. The motive behind the study is to improve the β-Ga₂O₃ MOS device performance along with a reduction in power losses and device associated leakages. To show the applicability of the designed device in RF applications, its RF FOMs are analyzed. With the outline characteristics of the ultrathin black phosphorous layer below the β-Ga₂O₃ channel region, the proposed device results in 1.09 times improvement in f_T, with 0.7 times lower C_gs, and 3.27 dB improved G_P in comparison to the NiO-GO MOSFET. The results indicate that the designed NiO-GO/BP MOSFET has better RF performance with improved power gain and low leakages.