Ferromagnetic insulators (FMIs) represent a class of quantum materials that integrate ferromagnetic ordering with insulating characteristics. These materials offer substantial benefits for spintronic devices: ferromagnetism ensures stable spin polarization, while their insulating nature prevents Joule heat loss. Consequently, FMIs are pivotal for advanced technologies, including low-power spin logic devices, magnetic insulator magnon flow manipulation, and magnetic storage systems free from Joule heat. Nevertheless, naturally occurring ferromagnetic insulators remain undiscovered, and the artificial creation of room-temperature ferromagnetic insulators is exceedingly uncommon. Specifically, within transition metal oxide systems, attaining a stable ferromagnetic insulating state at room temperature continues to pose a significant international research challenge, primarily due to the influence of strongly correlated electrons, multi-orbital coupling, and intricate interface effects.