This app was mentioned in 3 comments, with an average of 1.33 upvotes
https://play.google.com/store/apps/details?id=org.edx.mobile
Link for those on Android
Hi, this is a playlist on YouTube of all the lectures from 2021,from my understanding they are the same as those on EdX and Harvard's websites.
Based on my expeerince I would reccomend watching them on YouTube, you get the timestamps, comments etc. also the EdX video player is pretty annoying. If you travel a lot and would like to watch the lessons on the road, you can simply dowload the lessons via official EdX mobile app (for both iOS and Android).
And for Android users/losers: https://play.google.com/store/apps/details?id=org.edx.mobile&hl=en