Hi,
If I may jump in, this issue is even more intense with the Dark theme (which is amazing by the way).
Although I have the playlist undocked, its minimum width is still very large as you can see in the picture below (much larger than that of the default or classic themes), probably because of the distances between the buttons.
If you could do it as 265785 proposed, create two lines for the buttons on the playlist (or, if possible, move the playlist buttons of the Dark theme closer to each other), it would save us a lot of space.
By the way, the option for two lines would also be great for the Control bar, which is customizable (I have proposed this in another post some days ago, I hope you'll consider that too).
Thank you in advance,
Xenos