Incomplete Migration Assistant from External Drive

I have a new Mac Mini M4 so I created a backup using Time Machine from my previous Mac Mini to an external NVMe SSD (Crucial P3 Plus). The time machine back up was quick, I then started up my new machine and ran Migration Assistant from external drive. However when set up was complete I immediately noticed even my wallpaer was different. Then I logged in and none of my folders/files/apps are there. A few widgets are the same maybe. I go into 'Document' folder and it's empty and says 'Document - Local' ?

I'm not sure what's happened here