Nybble with RPI 4B+ HELP

Hello!

I just got and assembled my Nybble wih an RPI 4B+ on its back connected into serial like so. The issue is now I am unsure what to do. I have the Nyboard V1_2 switched to RPI Mode, and I am trying to control the robot over SSH. However, when I try to run ardSerial commands on the raspberry pi it just tells me that no board is connected. Ive also tried uploading arduino sketches to the board from the Pi on port dev/ttys0 but it always says failed to upload. The nyboard is responding as the remote works just fine. Does the Pi 4B+ just not work? Ive sen pictures of Nybbles with them before so I am confused. ANy help to get my robot moving using the Pi would mean the world.