This was an excellent adjustment to the code. My second level had a lot more blocks on it and the ball kept speeding up until you almost couldn’t follow it!
I tried your limit of 50 and while that kept it from getting as fast as before it was still pretty fast. I made maxVelocity be 25 in my second try and I think that was much more reasonable as a top speed, at least in my game.
An addition might be to also have a minimum value and then have a random change to it, so it can slow down and speed up slightly on each collision. Maybe make some blocks “sticky” to slow it down and others “bouncy” to speed it up.
I combined it with this and so far my ball never gets stuck in one place: VelocityTweak FIXED
The two together are a nice enhancement to the way the game behaves.