I have never seen this feature anywhere and it would be a really distinctive selling point in my opinion.
The Notepad (global and per track) is kinda useful but that’s not quite nice to use (plus, well the UI seems like 20 years old).
One thing that would be super useful would be to have some kind of sticky note that you can put anywhere in your project view to write text notes.
Like a pin that can be clicked and it expands allowing to write text.
I know I can do this with a marker but it is not what a marker is for, plus when you write long text it is not ideal.
Let say i have a track with a guitar solo i can just put a pin in the precise spot where I want to remark something and when I click it it expands so i can read or edit the content of the text.