New SDKs and Xcode 26 beta 2 just dropped.
Got the beta 2 SDK after a few tries. Looks like there aren't any changes for Liquid Glass in UIViews:
1) The cornerConfiguration API is still MIA
2) Setting the UIVisualEffectView's effect property to nil doesn't remove the glass effect.
Workarounds are still to use the layer.cornerRadius and alpha on stuff to make it look/work reasonably.