New Mac not finding old Mac on migration assistant
My new Mac not finding old Mac for migration assistant
My new Mac not finding old Mac for migration assistant
I'd say that the best you can do since you got a brand new Mac is to set it up as new. Take some time to install your apps, copy your files, etc.
This will grant you a clean OS, free from debris like old settings and files that could cause you some trouble.
New Mac not finding old Mac on migration assistant