And in the mean time prepare plans for lessons, answer questions, bringing resources for students use - they never were mostly or exclusively occupied by grading.
I haven’t encountered this platform before, but most textbooks now come with class plans for teachers (especially at university where they are used to kill off second hand book sales)
I mean, digital resources, bringing them ready to be used in class. Files have to be found, or better created from others by cutting and coupling, they have to be named, put in correct place for accessing. Even though the material sometimes doesn't change much form a year to another, it needs to be checked and adjusted for current class trajectory.
Teaching is a hard intellectual work. Good teaching, that is.
And the materials provided with the textbook often suck, and require more work to use than creating your own from scratch.
If the teachers don't grade anymore, what they are doing with all the free time ?