Migration Assistant creates a second admin account on Mac
I purchased a new Mac mini recently to replace an old iMAC (8 yrs). I set up the Mac mini first before trying to transfer all my data from the old Mac to the new Mac. I read in one of these support groups I can still use migration assistant to transfer the data I want to keep on my old Mac. When I use migration assistant, it wants me to create a second admin account on my new Mac mini in order to complete the transfer. If I do this, how can I put all the transferred data onto my new Mac in the new admin account and then delete the additional old admin account, if this is possible? Or is this a task I need to take to my local Apple Store so they can complete?
Mac mini, macOS 26.1