I want to scale the entire contents of a document to make them smaller. Changing the font size the usual way is not desired, as this changes how the text looks:
In other words, I want something similar to \scalebox{}{} or \resizebox{}{} — to change the size of the text without changing its font. I'm saying "size of the text" instead of "size of the font" or "font size" to clarify the difference from the readily available mechanism to change font size, which has the undesired side-effect of also changing the font itself ever so slightly.
What I can do, of course, is to just make the page bigger (i.e. use e.g. a3paper instead of a4paper, an approach taken here), but that seems like a dirty solution (if you'd print it out on A4 paper, however, it'd give pretty much exactly the desired output). I also don't want to change my \documentclass to KOMA-Script or such, as done here.
I tried \relscale{} from this answer and \scalefont{} from the scalefnt package, but these just seem to change the font size the usual way (as opposed to scaling the text directly, i.e. linearly scaling/changing font size). \resizebox and \scalebox don't respect linebreaks (manual or automatic), and I think they're not really intended made for modifying an entire document.
Ideally, the answer would behave just like e.g. \small or \footnotesize, in the sense that it'd be a switch that would affect its entire scope and work with math-mode, multicols, tabular, etc.
I hope this is not a duplicate, I couldn't find any answer to my question here (though, as mentioned above, there are a few similar questions). MWE not really applicable, but I'm using \documentclass{article} and compiling with LuaLaTeX (ideally, though, the answer would work with other documentclasses and with pdfLaTeX as well).
Edit: Tried to improve the question by rephrasing or clarifying.


\smallor\footnotesizethroughout the document -- which, of course, is entirely equivalent to setting a smaller font size to begin with. Please clarify what you're trying to accomplish. – Mico May 06 '20 at 12:12.txtfile, which, unlike LaTeX, doesn't change the font itself when changing the font size. – steve May 06 '20 at 12:18\resizebox. So, just give up on using Computer Modern (or Latin Modern) and find yourself a cheap font family that provides linearly-scaled font sizes. You'll be all set then. – Mico May 06 '20 at 12:32\smallor\footnotesizekeys anymore (if everything is\tiny, then\smallis suddently big), and that I'd also be limited by TeX's minimum font size of 2.5pt. Regarding legibility, well, that depends; if I want to print thea4paperon 200%, or just use a magnifying glass, or just have a cheatsheet with small text, then I think I should be allowed to. And I don't see any contradiction; I explicitly said I'm looking for something similar to\resizebox. – steve May 06 '20 at 12:36\DeclareFontShapecommand. – Steven B. Segletes May 06 '20 at 12:54