It is time for lecturers to swallow our pride and accept the "sage on the stage" is not that important to student learning. In place of large live events, I suggest the flipped approach. Provide videos and other materials for students to study in advance (you can provide quizzes to help). Then have online tutorials for small groups. The lecturer can record some short videos for them to use during the tutorials (I suggest around 60 seconds each).
Video conference systems, such as Zoom, allow for hundreds of students to take part in an online interactive events (Webinar). During the event the class can be divided into smaller groups, to work on a task for a few minutes, then the class brought back togehter. This is an excellent teaching method, however, it places demands on the technology, and staff which may be too much due to the COVID-19 Coronavirus. There is likely to be very high utilization of videoconferencing, straining resources. Also large complex real-time events are harder to organize.