Something I can do?

As @Thorr69 said, right now the PI4 model is not fully supported by RetroPie. If you flashed a Pi2/3 image, it won't work on the Pi4.

You can manually install RetroPie on the PI4 following the Manual installation guide. Support for this new model is ongoing and if you're just starting with RetroPie (or Linux), then is best to wait until an official release that supports the Pi4 will be announced.