Over the years, I've made very heavy use of open courseware/MOOCs. I'd estimate that I've covered about as much material in online lectures as I did in-person during a four year degree.
However, since college I've been frustrated by the general lack of online material for non-101 courses. Sites like coursera, edx, etc seem to have realized that the vast majority of users have basically no relevant background, so they optimize for users with no relevant background - they produce a very repetitive stream of 101-level courses. More advanced material is harder to come by online, even though it's abundant in university course catalogs.
But I hear that many colleges are moving courses online in response to coronavirus. So, a request for any professors out there: press "record" during lectures. You're on video already, you can sort out the details and decide whether to actually put up the recordings later, but for now just push the record button.