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.
KDE Plasma used to have one like the one on the right a few years ago, and I was so glad when they ditched it. I strongly prefer the organized look of the left one. I always had a hard time finding anything in the old KDE/MacOS settings.