I have the exact same question.

I’ve read a bunch of posts about this FBX * not installed issue. I’m unable to solve it myself, I’ve installed all the autodesk packages, restarted, reinstalled all the Xcode/Reality apps, updated to Big Sur and tried all the troubleshooting steps again. I’ve submitted a bug report, and we all should. In my case, changing my workflow was the only option. Blender 2.9 has a native .usd export setting, so that’s my workaround.

I've been following this tread for months. Nothing works for me. Installing all three packages installed in any order, restarting and upgrading from Catalina to Big Sur and various Big Sur beta versions still did not fix this for me. Late 2019 MacBook Pro, currently running Mac OS 11.3.1

This has been broken for me for about 8 months too. Broken in Catalina, Big Sur beta 11.2 & 11.3 and Big Sur public release 11.1. Currently not working in Xcode Version 12.4 (12D4e). I provided feedback months ago. I can connect to my iPhone via handoff elsewhere and I can connect to my iPhone just fine when I run a build in Xcode. It appears to be a bug in Reality Composer.

Same problem here.

This error also causes Xcode to hang and it's not possible to stop it or close the app unless I force quit.

Solved. Needed to manually add frameworks in Xcode. Not sure why it caused Xcode to hang though.

AR Quick look isn't technically Web AR, since it is OS level and not running on javascript in a browser. That said you can either link directly to the USDZ file or Reality file hosted on a webserver and this will open natively in AR Quick look. The cravat is this is only for Apple, if you want to have Android support you'll need to link to an html webpage and host two 3D assets in an html tag linked to both gltf and the Apple asset (usdz/reality) then the user can arrive at this html page, then navigate to the AR that is native to their hardware.

My understanding of AR Quick look is that it’s pretty locked down and limited in functionality. I this found in the docs: “AR Quick Look displays the contents of the HTML only. If you embed actions such as links or events, AR Quick Look ignores them.” https://developer.apple.com/documentation/arkit/adding_an_apple_pay_button_or_a_custom_action_in_ar_quick_look