No.
The display is always 5k.
It's the MacOS user interface which is addressable at 2560x1440.
The "looks like" settings in MacOS are zoom settings for the UI.
Yes, that's what I meant, the monitor is doing 60Hz at 5k and MacOS is rendering the UI at a usable 2560x1440 - which IMO it does great as you can get full 4k real estate in Final Cut / Adobe but have reasonable text in Xcode, etc.
Does having dual screen with different size, 4K vs 5k and different refresh rate cause any issues for work on Mac OS? Ie moving excels or browsers from one screen to the other etc..
I am thinking doing something similar once m4 Mac Studio comes out, originally was just going to get 2x studio display and call it a day but I want to connect a gaming pc to one of the monitor to play games so having a higher refresh monitor would be better as studio display 60hz sucks for game and it’s native 5k resolution is too much for most games even on an rtx4080
To me the most noticeable difference is the colors, the blacks on the OLED give the Samsung a greater contrast and the refresh rate makes interactions on it feel smoother. I have an old (~10yrs) Spyder calibrate device lying around but haven't been motivated enough to use it, not even sure if it supports this newer stuff (4k/5k, HDR).
They feel different but my usage pattern changed when I got the Samsung and use it for my 'primary' screen while the studio display typically has comm apps for work/family and occasionally I'll move a work window to it (Xcode, GitHub.com, etc).
I do love being able to have both the Mac & PC up at the same time, I have a dedicated keyboard for each and a USB KVM for mouse/speakers (but my Mac also has an always connected trackpad).
This whole thing for me came about because I wanted to be able to take game breaks during the day, on earlier Macs this was 10x easier. I'd play some whatever game on Intel Mac (like Diablo 3) and then get back to work. I ended up getting a gaming laptop that I'd hookup to my studio display and it sucked (5k, 60Hz) but rocked on my Sony 4k 120Hz OLED TV, so then I got the monitor on sale, and a week later picked up an HP Omen I'm going to use as a base of a custom build after Nvidia 50 series / AMD Ryzen 9 9000 X3D series propagate more and make the 7800/4090 more affordable (its funny how I spend so much more on Mac but am willing to wait for the PC stuff, probably b/c I mostly just game on it, but its a fun hobby for me too).