I want text-transform: uppercase to be “capital sharp s” aware

Currently, text-transform: uppercase turns the german ß into double S (SS), which was the official rule and therefore the correct behaviour for most of the time. However, since 2017 the capital sharp s is part of the official German orthography, and a lot of type designers are including the new glyph in their typefaces (Unicode U+1E9E).

Unfortunately there is no real workaround, besides hardcoding the capital sharp s into your markup, which is not always a practical solution.
I believe, text-transform: uppercase should check first if U+1E9E is available in the font and in this case make use of it. If there is no capital sharp s, the ß would be transformed into double S, according to the old rule.