Definitely. Besides the performance issues, back then, Teams barely had any features. One example was that it wouldn't show you who was talking. First time we had a call was with 30 people and I remember a manager calling out a director responsible for this decision jokingly saying, "and you don't know who I am because Team doesn't show you who's talking."

The UI is an overengineered mess and I'd rather use literally anything else, but to say it's still unusable is disingenuous.