I normally keep a blank song saved called “scratch” that I can quickly use to get an idea down then when I want to keep something I change the name within the song. I then create a new “scratch” song since there’s no “save as” function yet.
With this latest update 4.xxx changing the song name while the song is open doesn’t change the name of the song in the song list… it’s still named “scratch” but when I open it it’s called the new song name I re-saved it as.