That's super interesting, but at the same time, i think the primary concern is not if they are literally the same but if a user is likely to confuse them in a small font you dont have control over in a place they are not likely to pay attention to (e.g. addeess bar).

Like even if the two characters look quite different, if they both look like the same letter in different fonts that is a problem. It doesn't mattter if you can tell the difference between the glyphs in a side by side comparision. What matters is what letter the user interprets the glyph as.