How many songs can I fit on an Apple Watch SE 2 and how do I know how many are there?

I am wondering how one sees what's on the watch without looking there. In the Music part of the Watch App on my iPhone, I can add and see playlists but do nothing else. I want to manage just the downloaded stuff on the watch, but can't figure out how except to use Music on the phone or Mac and manipulate a playlist. But I don't know how much I can put there, or how much space is being used. Also, the Watch app incorrectly lists what's there (see screenshot below). Can anyone help with these issues? ha. Hoping for a better way to manage Music on a watch... is there a third-party app that does?