I tried air drop but it fails with large directories.
I also tried looking at the Time Machine backup of the old Mac but the new Mac doesn't have permission to see it for some reason.
As for migration assistant, I don't think it allows you to copy a home directory from your old Mac to a subdirectory of your home directory in your new Mac.
So what should I try?
P.S. It seems that I can't use a Time Machine external disk to copy files back and forth, even manually using "cp -rp".
https://support.apple.com/guide/mac-help/transfer-files-mac-...
If one or both Macs are Apple Silicon, try this: https://support.apple.com/guide/mac-help/transfer-files-a-ma...