I just have a TBR, it is a list of books I haven't read yet but would like to. That seems to be more the definition.
If one of the books on it is vastly more important, it is probably because it was just magically transported into my "in-the-middle-of-reading" list.
(It isn't "to be" read, if it is "currently being" read.)
(Yes, I have an actual list of books I am concurrently reading.)
Do people really waste time
ranking their TBR when they could be reading it?