The first launch of SpaceX's Crew Dragon with astronauts on-board holds the record for the most concurrent internet viewers on a stream tracked by NASA at 10 million.
Of course if you drop the internet requirement, Apollo 11 still is by far the most live viewed at 600 million viewers.
That makes sense for Apollo 11. I expect that one won't be beat until we land people on Mars. I figured SpaceX had some much bigger viewerships than 10's of thousands. (I've watched several myself.) That number must have been on the more (now) regular things like vertical landing the same rocket for the Nth time! Thank you for the update.