I'm also having issues on Xcode 26 RC. I somehow managed to get it to compile, though unsure what or how, but after a reboot it went back to being broken. I'm also unable to run sudo rm -rf /System/Library/AssetsV2/com_apple_MobileAsset_MetalToolchain/, it errors saying Operation not permitted. The folder contains two .asset folders if that's anything noteworthy.

I'm having the same issue on iOS 17.2. While the workaround does work, it's not feasible for my usecase. Would be great if Apple could fix this