I still have this behaviour. M1 Pro, Tahoe, xCode 26.0.1 (17A400). After updating to Tahoe updated the xCode. xCode says now that I don't have any simulators (altho I can manually run Simulator that was preinstalled with xCode). Also downloading from xCode UI fails instantly with the same issue author mentioned. Running command xcodebuild... -> also fails with DVTDownloadable: Download Failed (iOS 26.0 Simulator (23A343). Tried reinstalling xCode, reloading, rebooting, nothing works so far.