For context, I just tried the reading mode. One problem I noticed was there was the usual play button and a start timer button. I would suggest it function the same as regular “watch mode” where hitting the play button would auto-start the timer(I’m aware of the option in the reading setting). Remove the “Start timer” button.
Another suggestion would be to auto-check the “read” button when the video ends or the last line audio in the transcript finishes.
Lastly, for the daily goal/study bar at the very top accounts for all the modes. Either it could be linked with the chart type options, where selecting a different data type would reflect what displays on the bar or a much more straightforward way would be to just show a different color. So if a user/learner has a goal set for 1 hour and he does 30 minutes of reading and 30 minutes of watching, the bar would be half-red and half-blue(default color).