I don't know about you - but the "shelves" UI that current System Preferences uses is - hard to navigate. There's no real rhyme or reason for the shelf location.

At least the Ventura/iOS multiple menus has a hierarchy. Ultimately I use "search" for such large settings to find stuff like 90% the time.

why is wifi/bluetooth/network/vpn separately laid out instead of being in a single "network" like i assume was in the old ui?

I think the sidebar is a big improvement and I think it is nice that you can quickly get to the network items you need. It's the right hand side that is awful.