As per the conclusions of that great video, going back before Pong and defining a "first" video game depends heavily on your definition of both "video" and "game"
I don't think it is unreasonable to define a "video game" as one employing video graphics and real time input. Things like Tennis for Two (and the later Spacewar) are clearly video games in a sense that mere simulations of board games are not.
I built a basic version of Tennis for Two a while back, using regular op amps. Some modern oscilloscopes have bad X-Y mode implementations, but most non-extremely-cheap scopes are probably decent enough. https://blog.qiqitori.com/2024/08/implementing-tennis-for-tw...
I'm also planning on selling a kit in the near future!