In the context of low-dimensional materials, incorporating foreign atoms through doping processes has the potential to modulate the properties of host materials, which is favorable for diverse functional applications. In this study, we introduce a series of six distinct B6P6X ternary graphenylene monolayers. The B6P6X is designed through interstitial X = Cl, Br, I, O, S, and Te atomic doping of pure BP graphenylene. Through spin-polarized density functional theory (DFT), we comprehensively investigate the stability, electronic, and magnetic properties of B6P6X monolayers. We demonstrate that B6P6X monolayers are mechanically, dynamically and thermally stable with ferromagnetic ground state properties. We show that the metallic features of B6P6X (X = Cl, Br, I, O, S) and half-metallic property of B6P6Te monolayers at the PBE level can be further modulated when subjected to the HSE06 level. It is revealed that the B6P6X (X = O, S) monolayers exhibit a sizeable magnetic moment and a large magnetic anisotropy energy (MAE) value with an easy out-of-plane magnetization axis. We also found an out-of-plane MAE magnetization axis for B6P6X (X = Br, I) monolayers and an in-plane easy magnetization axis for B6P6X (X = Cl, Te) monolayers. Further investigation show that the B6P6S monolayer exhibit above room-temperature TC up to 565 K. The estimated Berezinskii–Kosterlitz–Thouless transition (BKT) temperature value of B6P6Te monolayer is 254 K. Our findings show that the B6P6X monolayers, particularly doped with chalcogens are potential candidates for nanoscale electronics and spintronics applications.