You could use this part: https://www.teoria.com/en/exercises/ic.php. Teoria indeed always reverts around hearing what you do and reading it from formal notation. I think that's a reasonable design choice, but it of course goes beyond simply drilling intervals into you. To be honest, I used physical flash cards for the really basic stuff, like "What notes are in an E-major7 Chord?" I still have them and they served me very well. (: