The paper explores the orbital Hall effect (OHE) in two-dimensional (2D) ferromagnets, focusing on the role of topological phase transitions (TPTs). The authors demonstrate that TPTs can efficiently engineer the OHE by controlling the orbital angular momentum (OAM) distribution through band inversion. Using first-principles calculations, they identify Janus RuBrCl and three septuple layers of MnBi$_2$Te$_4$ as experimentally feasible materials for this purpose. The study highlights the potential of topological engineering to modulate the OHE, opening new avenues for innovative applications in topological spintronics and orbitronics. The research provides a robust methodology to control the OHE, which could lead to significant advancements in various fields such as transport, information technology, and magnetic electrical control.The paper explores the orbital Hall effect (OHE) in two-dimensional (2D) ferromagnets, focusing on the role of topological phase transitions (TPTs). The authors demonstrate that TPTs can efficiently engineer the OHE by controlling the orbital angular momentum (OAM) distribution through band inversion. Using first-principles calculations, they identify Janus RuBrCl and three septuple layers of MnBi$_2$Te$_4$ as experimentally feasible materials for this purpose. The study highlights the potential of topological engineering to modulate the OHE, opening new avenues for innovative applications in topological spintronics and orbitronics. The research provides a robust methodology to control the OHE, which could lead to significant advancements in various fields such as transport, information technology, and magnetic electrical control.