Based on this product's specifications, here are some alternatives and similar models
Filter Black Diffusion 1/4 for Camera DJI Osmo Action 6 / Action6 by K&F (MPN SB11155)
Summary description:
Black Diffusion 1/4 filter designed for use with DJI Osmo Action 6 and Action6 cameras. Manufactured by K&F (MPN SB11155), this diffusion filter reduces contrast and softens highlights to create smoother skin tones and a gentler look in video and photo capture. It mounts to the camera lens to control highlights, bloom, and overall image diffusion for portrait, vlog, and cinematic recording.