In LibreOffice Draw, is there an option to automatically set the page size to fit a selected object? I know there is a way to fit an object to the page, but is the vice-verse possible? If so, how? Thanks.
Not that I know of. I am curious about your suggested method “to fit an object to the page.” The latter sounds to me like you are thinking of the Fit object to paper format accessed via Format > Page… > Page tab > Layout settings section. Selecting this (according to the help page) simply ensure Draw/Impress slides are scaled to fit on the paper they are to be printed on, thus the term “paper” rather than “page” in the option.
I completely agree. It would be good to have this/these features in Draw. Related enhancement request is fdo#67952.
As a workaround, you can manually change the page size.