Bill, what you state has no relation to what I am describing. HDMI scaling controls the size of the visual display in relation to the display device. In no sense has it anything to do with a browser. Setting an HDMI scaling control affects everything displayed.
HDMI scaling is very much like printing something from your printer that will not fit properly on the sheet of paper. You change the printer setting to 'fit to page' and all is well.
What you describe as to web sites is more likely due to the browser magnification settings. Edge seems to display larger than some other browsers. 125% magnification seems to equal about 300% in IE or FF. An author of a site can only do so much as to this regard. One can only look for a balance. In IE and/or FF this site displays fine up to, at least 400% magnification. One can only do so much from the author side.
Even though IE is obviously being phased out Edge still needs a lot of work to be a proper browser. While I have not researched I would guess that Microsoft has separated Edge from the W3C web guidelines. If that is the case it is not a good thing. At the same magnification that I usually use, 125%, Edge will display these forums at, at least, twice the size of either IE or FF. This is not likely the fault of the site code but, rather, a fault in the browser. Think Occam's razor. Since two browsers are fine, and one not, Occam's razor would indicate that it is the fault of the third browser as it is the simplest solution.
For those that do not know Occam's razor it is a principle that states that all things being equal as to input the simplest solution is usually correct. I could type pages on this but that is enough for the general principle.