I have been doing some online teaching for a university in China. There have been some challenges, perhaps largely due to too little notice about preparing and difficulties in communication.
Something that surprised me was that the original intention was that I would teach oral skills to a class sitting in a classroom with one shared microphone. So, I was sitting in my room in Bristol seeing students and they could see me through a screen. I would say something and responses involved students passing the microphone around the classroom. This was clearly a very ineffective way of teaching.
Eventually, I managed to persuade the College to change the model so that students were working outside the classroom on individual computers or using the phone. However, we were using Dingtalk and I was told that breakout rooms were not possible. So, although the communication was improved, I was not able to monitor group work or even have any idea if it was actually taking place.