Notarization works well from the Xcode UI, but the moment you want to handle this from the command line it's mostly trial and error. At least I have a shell script now that handles all commands for me. And this support page by Apple: https://developer.apple.com/documentation/security/notarizing_your_app_before_distribution/resolving_common_notarization_issues
[Notice Regarding the Transfer of the mstdn.jp / mastodon.cloud Services] We have received several inquiries showing interest in a transfer following the announcement of the end of the mstdn.jp and mastodon.cloud services. As a result of subsequently evaluating the situation and making preparations, we have decided that the corresponding services will be transferred to Sujitech, LLC. on June 30. Thank you.