Read the other comments. The video creator is literally adding artificial latency and then complaining about bad performance.
Watch the video, he does both no latency and introduced latency. And is quite up front about it. Nothing wrong with his methodology at all.
the app does not work, I dont have internet. the app and the owners are terrible developers. that sums the video.
Nah, creating duplicate calendar entries because you did not receive visual feedback before getting frustrated and making another one sucks. Maybe watch the video instead reading the bullshit the narrative drivers are feeding you.