I made a font with German letters, alternate letters (umlauts - Ä, Ö, Ü & ä, ö, ü) and the special character the “Eszett” ( ß ). I can type fine both lower and upper-case but when I hold shift it flips the case. I tried Alt + (letter) but that did not do anything but open a menu in Illustrator 2021 that did not pertain to the font.
P.S. the alternate for an upper-case ‘B’ is the Eszett but that does not happen.