The image on the right is how the settings app look on macOS 12. On macOS 13 (2022) it was changed to look more to the one on the left, with all the sections selectable in a sidebar and a smaller window. Many users have complained about it, saying that it sacrificed function for form and is part of making macOS more like iOS by mindlessly copying phone UIs onto computers which it isn’t meant for. I think its alright, not terrible. And it’s the norm with settings apps looking like that in Windows, KDE, Gnome, and some other DEs.
I’m so much more used to the left that I absolutely do not like the right at all. Side note: it’s why I absolutely disliked default Gnome when I was first using Ubuntu: programs set up similarly to the right in the start menu adjacent thing.