Solved!
I had confused too. I didn't see Sandbox user in Settings > App Store. Then I read documentation :-)
In iOS and iPadOS, the sandbox account appears in Settings > App Store after the first time you use the device to attempt a purchase in a development-signed app. There’s no need to sign out of the non-Sandbox Apple ID. Sign in using a Sandbox Apple ID.
nikita_cz
Users receive reputation points by contributing quality content to the forums.
Posts include post and replies published on the forums.
Post authors can mark replies as Accepted to indicate successful solutions.
Apple Developer Forums admins can mark replies as Apple Recommended to indicate an approved solution
Last seen
User for
From
Prague, Czechia
Post
Replies
Boosts
Views
Activity
I had same issue with definition: "There are still screenshot uploads in progress". Resolved via AppStore Connect API. Solution is here: stackoverflow
Resolved by uploading a new build via Xcode (build version == AppStoreConnect version)
Workaround: in Xcode, create an Archive, then click "Distribute App". During the upload, the App will be created with your bundle ID.