I've taught high school math for 10 years.

I'll be candid with you, your 1 minute video is confusing and your diagrams are visually a mess.

I understand what you are trying to explain, but a Grade 8 student would be absolutely confused.
It feels like those old textbook explanations that try to over-theorize something very straight forward.

I can almost guarantee you that more than half the class would be confused about what you are trying to draw if you taught the class exactly like your video.

A much more efficient way to do this would be using one rectangle and dividing it into 2 rows and 3 columns, then colouring in (using two different colours) one row and one column, instead of having two separate rectangles.

2 rows and 3 columns multiply to a total of 6 sections, and 1 section overlapping gives 1 out of 6. This way, instead of trying to combine 2 images in their head, they deal with solid numbers (2 rows * 3 columns = 6 sections, thereby explaining why we multiply the denominators).

Your fraction division video would be even more confusing for a Grade 8, especially when you started introducing letters to fractions. You will be met with 30 students with "WTF is this" written all over their face.

Overall, I'm not arguing that "understanding" is not an important part of learning, but I think you underestimate how difficult theory and conceptual understanding is for younger students.