I believe the UI is being managed to death. I noticed the same with Slack recently.

The old UI was probably built by engineers for performance and ease of use.

The new one is pretty, does all the stuff marketing wants, has loads of features, uses shiny new tech. Or, all the original engineers that knew how to build a good site left. Maybe both.

It's a dumpster fire. I haven't found anyone that disagrees and I have all the same bugs you do.