PlayCanvas uses WebGL 2 by default and falls back to WebGL 1 when it's not available. So in Safari, the renderer will use WebGL 1. Just tried the link on a recent MacBook Pro and an iPhone X and XS and it works fine. What is your OS and Safari version?
Ah! I had that turned on. Thanks! What is the default for these experiments? I can see me turning that one on, but a lot of others are enabled that don’t make sense to me.