I maintain a nodejs based atem library
https://github.com/Sofie-Automation/sofie-atem-connection, and I will suggest that doing it on an arduino is not going to be easy, if it is even possible.
a majority of the protocol hasnt changed since well before 7.5.2, but after that version they introduced the largest model which more than doubles the amount of properties that the previous largest model has, which I expect is what made existing arduino libraries not able to cope with the volume of data
While it is udp, it requires performing various steps to run a stateful connection over udp. And upon establishing this connection the atem will send a snapshot of its current state to you, which depending on the model of atem will be 12-100kb of data which. messages must be acked within a short timeframe or they will be retransmitted.
for your use case, you probably don't care about any of that data it sends, so maybe you could pull it off to quickly discard the data and ack the last packet? I would be worried about overloading the arduino with this much data though.
once open, you could construct and send the packet you need (which will require some understanding of how to form packets, with sequence numbers, flags etc) send it and then leave the connection timeout or perform the minimum to keep the connection alive (messages every few hundred milliseconds).