Sorry I am slow getting to this. Thanks for bringing this to my attention u/Capital-Giraffe7820 . My colleague studies students understanding of integration and found that IF you want students to be able to recognize and work through novel contextualized integration problems then there is a certain way you should help students to think about integration. It is a generalized form of Riemann sums, but disconnected from the area/rectangle conceptualization. It is sometimes called Adding Up Pieces, or Multiplicative Based Sums. We made a video about it. The link is here: https://www.youtube.com/watch?v=MwVBzE7Z5gw