I have LineageOS on my phone and noticed the media player has the wavy progress bar on it. Not only that, a lot of music players also have it and lowkey I personally don’t like them. I find it hard to position where I actually want to be in the song and I just don’t like the constant movement. I rather a normal progress bar but that just a personal choose.
the incredibly stupid part is that on the developers side it was in alpha/beta for a long time. you literally had to use a beta version of the material library to add a progress bar, because the older one was not included. I’m not even sure it’s ready now