I like to keep it together at least for now. And i hope Samsung will keep supporting both arrangements
I find "together" more ergonomic for one handed operations - and i think that's the core value of OneUI: everything is designed for one-handed use no matter how big your phablet can be. Keep in mind that Samsung revolutionised the use of bigger than usual thouch screen phones - from the first galaxy note and i think they keep on improving it up to the current galaxy S ultra series.
With "together" arrangement, i still get access to my mostly used settings while checking my notifications - all in one swipe of a finger. I just need to swipe down again if i want more settings but that isn't a big deal for me and it rarely happens because automations got the other settings (like Bluetooth and WiFi) covered.
I rarely change most of my settings manually
Some buttons are accessible through other gestures
Some settings are just a swipe away and some are accessed through physical buttons
I see a possibility of unintentional dismissal of notifications when i use the "separate" arrangement and decided i want to go from notification shade to quick settings panel by swiping to the right page. I think i have to swipe at the bottom or at the top to avoid swiping any notification.
If you want them separate, you feel it's modern and more intuitive for you esp because you got accustomed to how iPhones work (Google will probably follow this come Android 16 - wow OneUI is ...), I'm not against it. But "together" is the easier for me, for now. I'm trying the newer arrangement from time to time, i still go back to "together".
