There is a feature request for this in https://jira.atlassian.com/browse/CLOUD-6999 If you read the latest update from this past March, there appears to be a private beta program you can try to register for. It's no guarantee that you might be eligible to do this yet, but you could try that.
I would recommend watching and tracking this issue. Should Atlassian begin to offer this as a service some day in the future, this ticket will be updated to reflect that.
1. Cloud does not yet allow you to change the base url for a Cloud system - the only way to do it is a replacement - "buy a new one, export from the old one and import into new"
2. Cloud does not yet support anything outside the Cloud domain. The url must end with .atlassian.net
Both of these are things Atlassian want to support in the future, but I've no timetable for when they may happen
Hi @Timo Achilles,
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