I actually wrote about that yesterday: https://taoofmac.com/space/blog/2020/07/11/1830
I’m doing roughly four hours of 30m calls a day (which completely destroys any real productivity I have), plus around two hours of actual “focus time”. The overhead and fragmentation implied pushes this to a 10-12h daily range, which is becoming a serious issue as I can’t find the time to plan or do quality work right now.