Unreal Engine 5 can run in your browser. What "3D rendering" capability is missing for video work?

Unreal Engine 5 can limp on my browser, and usually most demos end up crashing it, not really a good example.

What is the most successful game on the browser, done with Unreal 5 that can compare to Flash 3D games, other than the citadel demo done with Unreal 3, and with Infinity Blade graphics as baseline?

Exactly, crickets.