Users should be able to change their username to a collection alias already in use, as long as they also own that blog. This simply makes a secondary blog into their primary one.
Previously requested on the forum:
- https://discuss.write.as/t/tedium-free-method-for-replacing-default-blog-username-with-secondary-blog-username/3375 (Aug '21)
- https://discuss.write.as/t/deleting-primary-blog/4572 (Feb '22)
Also requested privately.
Before changing primary collection name and adding a redirect, check if the collection exists and is owned by the user. If so, skip those steps and save the new username information.