@jps: thanks. It shows: "DPI scale: 1.729", which is in line with the settings I made (DPI 166 instead of DPI 96, which would result in "DPI scale: 1" in ST).
I guess why ST differs is b/c other apps use both the DPI scaling factor AND the font-size from the DE settings. It seems ST chrome fontsize is not derived from the DE settings.
If font-size is a setting for chrome fonts within themes, it might be a setting app-wide?