Videos play in low quality when projected on a sphere using VideoMaterial

Is there any way to play panoramic or 360 videos in an immersive space, without using VideoMaterial on a sphere? I've tried using local videos with 4k and 8k quality and all of them look pixelated using this approach. I tried both simulator as well as the real device, and I can't ever get a high-quality playback. If the video is played on a regular 2D player, on the other hand, it shows the expected quality.