Changing handles is a common feature on websites, and request on those that don’t. There are probably good arguments for both from both usability and technical standpoints. FA doesn’t support changing names, its been a request for many years at this point. Weasyl allows you to change, and the most recent old name will redirect. I know SF and IB both allow name changes, but I don’t remember the details, I think one had a previously known as label that could be shown. You can’t allow perpetually holding a name, I can think of many malicious ways to abuse that. Bluesky has the did for perpetual static links, it doesn’t change because that is what all the data is really tied to, the handle is just a nicety.