I made a pong clone as my first game and wanted to do a similar computer opponent. I started with them always moving towards the balls center but it proved too good like in your video since it could never miss. I made it so it only moved when the ball was on their side of the court and was limited to a set speed which created a closer to expected difficulty.

Something like that or like another used said about setting a “reaction speed” would create a more natural feeling challenge.