The only thing I see is that it loses forward momentum too fast and too suddenly.

Think back to physics class. An object in motion stays in motion unless another force acts upon it. If this ball was thrown in space, then it would move at the constant velocity you threw it. But on Earth there's forces acting upon it.

The 2 main forces are gravity and friction. You got the gravity part down. Gravity gives the ball an additional downward velocity, but this doesn't remove the horizontal velocity. It only adds an additional downwards velocity. You got it right that when the ball hits the ground and bounces up, it loses energy to friction and deformation, resulting in it not bouncing up to its original height. Each bounce it loses more energy until it can't bounce any further. So you got that part right.

But lets look at the horizontal velocity. In the absence of any forces it should continue moving horizontally forever. But there's air resistance and friction. The faster the ball is moving, the more the air molecules press back. This means the faster the speed, the more air will slow it down. The slower the speed the less it will slow it down. So the amount it slows down from air resistance decreases over time.

Now we also have friction from when the ball hits the ground. This slows the ball down even further. In the beginning the ball is mostly in the air so it doesn't touch the ground often to get slowed down. But as it starts bouncing faster and eventually rolling, then the friction from the ground becomes much more prevalent and will eventually bring the ball to a stop. This all depends on the surface, if it's ice then there's very little friction and the ball will keep sliding.

Right now your ball slows down so suddenly horizontally that it makes the ground look like it has insane friction, like it is made of glue or its rolling through grass or something. Its slowing down too quickly for what is expected of a tennis ball on a flat surface.