Since I upgraded to Catalina, the NPW does not appear if the Music App is not open and running or a "playing app" like Safari, QuickTime, etc. Once a "playing app" is running, the widget appears and does the work as intended.
Although, what I have found interesting is that if I use "Show only icon, no text" the placeholder appears but empty, and stays visible even if no "playing app" is running, then, it will open the Music App, show the Album Art (my choice of icon), and start playing the first album in the list if I tap on the placeholder, which is the behaviour that I has seeing before, but without the Line1 and Line 2 texts being shown.
Is this related to the disappearing of iTunes and that the widget needs updating? If yes, then consider my post as closed as I will wait for its update, if not, please let me know how I can help.
MBP 2018, Catalina official release. BTT build 1382