Krafton maintains a whitelist. Currently, these devices natively support 90 FPS in BGMI:
Unlocking 90 FPS in Battlegrounds Mobile India (BGMI) allows for ultra-smooth gameplay by increasing the frame rate beyond the standard 60 FPS cap. While Krafton officially supports 90 FPS on specific high-end devices, users with capable hardware that lacks the official setting often turn to configuration files to manually enable this feature. Key Features of a 90 FPS Config Bgmi 90 Fps Config File -UPD- Download
Using third-party config files involves modifying game data, which carries significant risks: Krafton maintains a whitelist