Yes, I upgraded my iphone XSMax to the public iOS14 and it bricked. Trying to restore now following the instructions below.

I have the same experience as Prebrules. I can get it to recovery mode and I can reinstall the OS, but it reinstalls iOS 14. It takes me to the "Hello" screen and lasts about 10 mins before crashing and rebooting. Clearly iOS14 doesn't work my iPhone XS. I can't figure out how to install iOS 13 from recovery mode. So I think my only option is to wait for a new iOS14 release from apple and then install this through recovery mode. Any other ideas appreciated.

After spending 10 hours on this, i eventually got it to downgrade to iOS13. What a pain.