+1 for that TB4 hub and the DP cable.
In principle, for somebody coming form a 27" iMac I’d suggest to get a 5K screen, but they’re really expensive and there’s still hardly any selection to choose from these days. TVs are 4K (or perhaps 8K) and that’s where the bulk of effort lies, so that’s what shows a lot of choice and has its prices driven down. No TV market at 5K.
So next best thing. 3840x2160 is the the natural 2x oversampling of the old-school 1080p resolution. While 1080p on a 27" is garbage (at least for a desktop computer) doubling it on a 27" just makes for very crisp text and beautiful images.
I’m using this Dell U2720Q and running it at 2560x1440 like my old pre-retina 27". Like all non-Apple screens this Dell is plastic, but it has very thin bezels and a fairly minimalist design so there’s not much ugliness you have to look at. The panel, however, is absolutely excellent. Bright and sharp, good color accuracy, no funny business. Along with full maneuverability (height, tilt, swivel, rotation), fairly intuituve and simple on-screen display options, and multiple inputs so you can connect several Macs (or PCs) it just makes for an all-around great display. I’ve always been very happy with high-end Dell displays (I otherwise can’t stand the company) and with this model again I’ve been very pleased (except for this minor detail).
Note, there’s also the U2720QM model, which is the exact same display but ships with HDMI cable instead of DP—I’m told M signifies consumer/home use and hence the different cable. But the rest is perfectly identical.
It would be really sweet if Apple released a 5K screen for regular/semi-pro desktop users. Basically an iMac without the iMac. Well, and some height/swivel adjustment. I won’t even dare ask for multiple inputs. When was the last time Apple ever did that? ;) 5K iMac starts at $1799. If Apple would sell the 5K display for $999, they should be making a boat load of money. I doubt the kind of folks whose work requires them to fork over $5k for an XDR would ever consider getting such a pleb screen instead. ;) But $1k heading Apple’s way instead of $700 going to Dell should make Tim at al. at least a tiny bit giddy.