Merge
Fragment of a discussion from User talk:Amire80/LiquidThreads
We have mw:Extension:UserMerge here but it's traditionally only used to delete spam accounts (which was no longer needed since the Translate sandbox). In theory, since the actor table migration such merges should no longer be a big deal technically, but we've not tried on big users yet. You don't have many edits so we could try. It's probably better to merge the new account into the old and then move it to the new username if needed.
Which username do you want to keep? (Please confirm with the other account too.)
That said, if you just want to avoid emails then maybe you can disable email notifications and be done with it. :)