We are trying so hard to use Teams, but the performance is just not up to snuff. They took a shortcut using Electron to get it cross-platform. For such a large pervasive company, I don't think this shortcut is worth it as they should have just invested in native like their other desktop apps. It's going to hurt them long term in my opinion. I even submitted a user voice about the memory issue and slow UI.

Pretty sure they are working on a Universal App for Windows. Which means many of your concerns could be addressed. I haven't noticed any issues with the OSX version, but I don't use my Mac much.

Not related to your post, but I just need to tell someone. Literally nobody in my company has managed to understand the threaded messaging in Teams, even after it's pointed out/explained to them.