From what Michael Hamann said, it seems that we would need a config option since if we choose one solution over another we'll always have users expecting the other one.

I think that those appearing at the end of the chapter are called endnotes while those at the bottom of the page are properly footnotes (see e.g. https://proofed.com/writing-tips/footnotes-endnotes/ ). So, rather than a config option this probably calls for two different macros.