I use a 4k 28inch as my primary monitor for code at home (laptop screen has email and slack). I run i3wm and typically code with 4 terminals windows next splitting the monitor into 4 equal sub windows, each having 1080p and running vim. It's very nice and whenever I have to visit the office and is stuck with their 1080p monitors I find my self severely limited because I'm so used to my home setup.

I've been "coding" on dual 27" 4K@60 displays for years. Can't go back to lo-dpi displays after getting used to having truly legible/beautiful text rendering.

I love my pair of 32" 4k monitors for coding. Screen real-estate lets me have everything I want open, open. I don't have to go digging for windows. I don't have to worry about arranging windows carefully. I get to see a lot of code, and a lot of terminal history.

Gaming and TV on the other hand, I'm perfectly happy with a smaller 1080p monitor. There just isn't much to be gained by a few more pixels.

Inches don't matter. Pixels per degree matter. And my desktop screen takes up a wider angle than a TV would.

Even just being close in angle would suggest 4k is good.

Text on monitors has traditionally never been able to have crisp curves. High pixel densities help a lot with that.

I use a 24" 4K at 200% scaling for the razor-sharp text. It helps a lot for text heavy stuff like coding.

I use one and pixel double the display to 1080p.

Mac displays have spoiled me...

There are lots of 30-32" 4k displays out there.