How can you change the bundle ID in step 2? Everything I'm seeing says "... It can't be changed after you upload your first build."

I'm seeing the same issue. The call to https://p42-contentws.icloud.com/ArdvyhXYU6B_cI2d1bexUjDHgK0a_NbxsGOVLZ6m_6F5b0D78jRvremnjLozOdzr0YfpN0_h26zHPLks5eM_H_c/singleFileUpload?... is failing with "Failed to load resource: A server with the specified hostname could not be found." This is happening when trying to upload a 110KB jpeg image as an Asset via the CloudKit Dashboard. Tried in both Safari and Chrome after clearing cache/cookies. Even tried on iOS Safari over cellular data rather than my home WiFi for the heck of it (13 Pro running 15.2). macOS 12.1 Safari Version 15.2 (17612.3.6.1.6) Chrome Version 96.0.4664.110 (Official Build) (x86_64)