I honestly feel Steam is also incredibly slow compared to just opening their site in a browser. All of these game launchers are just janky DRM and some of the worst software our industry has to offer.
Not only did they get rid of the cool 3d menus made with actually rendered 3d models (mdx) but they swapped them to webms instead (lost a lot of unique animations).
Anyways, the UI loads incredibly slow, it's very laggy, yet if you open it in browser, it is actually fairly smooth, what is going on? nobody can tell.