The capital ẞ is a recent invention, it’s in Unicode since 2008. While it would solve the issue, most programming languages and other tools will convert it to S

The capital ẞ is a recent invention, it’s in Unicode since 2008. While it would solve the issue, most programming languages and other tools will convert it to SS (though things are changing; Gboard now offers an actual uppercase ẞ instead of the SS it had some years ago). I don’t know what actual humans think, but I suppose the no-capital-ß-exists position is ingrained in many German speakers.