maybe this is well known… Order-Independent-Transparancy makes the surfaces invisible on Safari on iOS. E.g. this playground https://playground.babylonjs.com/#TMDNDM#70 shows no sphere on Safari on iOS (18.6.2). It does in all desktop browsers I could test.
I know, it’s a beta feature… so I need to disable it for our Cabri3D for Safari-on-iOS (that makes, any browser on iOS currently, I think). I would be interested to hear if this is a working topic…