Steam is one of the worst software, it's frankly embarassing for such a huge company. It's a hotchpotch of different design principles and new features only get tacked on with a very different UI + UX. The client is mostly webviews but they are so slow and buggy and they use a very old insecure Chromium version under the hood. The launcher is still a 32 bit program. It's sad that other launchers are even worse though.