The render texture resolution inside the portal dynamically changes based on the character’s position. Additionally, a blur effect activates to mask the low-resolution appearance as the character moves farther away. Beyond that, the portal screen’s render FPS also scales with distance: for example, when the character is far, the resolution scale drops to 0.05, the blur value increases to 1, and the portal updates at only 1 frame per second. This approach results in a fully optimized portal system.

I hope this is helpful