Do you believe pixel shaders are some unique magic that only Apple has the secret sauce to and noone else can use? There were some efficient implementations of liquid glass for flutter before the iOS beta was even released. Glass effects are dime a dozen on shadertoy, they're one of the most basic effects you could learn to do when learning about texture sampling.

The platforms that will take a large performance hit are the ones that can't drop down to the native platforms, i.e. the web.