Hostname updated everywhere except login/lock screen

I completed using Time Machine and an external hard drive to migrate from an older MacBook Pro (Epsilon) to a new one (Savathun), both running Big Sur 11.4. I then completed all Sharing settings to update the Savathun's hostname, both remote and local. Other computers on my network see the new Mac as "Savathun," and my terminal prompt shows "Savathun." However, the hostname displayed in the lower middle of the login and lock screens is still "Epsilon."

Where is this hostname value coming from on the login and lock screens? I'd like to update that if possible, even if I need to dive into a file and do a manual update.