One curved monitor vs. 2 or 3 non-curved for software development

I have always preferred a single big monitor vs multiple smaller monitors, since I prefer to switch workspaces (AKA 'virtual desktops' or 'spaces') over turning my head. Make sure your setup, whatever it is, allows for switching workspaces quickly and easily from the keyboard.

I used to have a 38" curved ultra-wide (LG 38UC99-W). The main thing I hated about it was the lack of vertical space. Ultra-wide might be fine for gaming or media production, but it's terrible (IMO) for development work. I also did not enjoy the curve because it seemed to make it harder to get a consistently good viewing angle. I suspect curved vs flat is mostly just personal preference, though.

I now use a single 43" flat monitor (Dell U4320Q), and it is great. More than enough space in both dimensions. For terminal work, I often tile them 2x2, or do "1 big, two small" in either horizontal or vertical. For my IDE, with its own separate-reality-UI-paradigm-in-a-window obnoxiousness, I let it take over the entire screen. I also keep my browser maximized, so I can keep a big vertical tab bar and my devtools open at all times. I like to keep my fonts quite large because I feel like it reduces eye fatigue at the end of the day.

One last piece of advice: ditch the stock stands and get some nice monitor arms. I consider this absolutely necessary. I cannot believe it when my fellow developers use the terrible monitor stands included in the box. They almost always have poor adjustability. Monitor arms are relatively inexpensive, and make it so much easier to get a comfortable, ergonomic setup. Not to mention they allow me to make bigger adjustments when I switch from sitting to standing. Plus, I can lift up my heavy monitor on its gas cylinder to access its ports and dust under it more easily.

I mostly only use one 27", which is not curved. I am fine with only using one as I don't like to constantly turn my head. As for the size, I have never used a larger screen, so I cannot tell if I would like that better or not. I don't even use virtual desktops that often, I am just constantly switching opened windows with alt+tab and very fast with that.

One idea is to search Amazon for different Monitor Desk Clamps for inspiration. There's a lot of different setups for monitors where you can arrange stuff with flexibility and even have your laptop elevated in a comfortable spot.

Having recently bought a curved monitor, I would buy a 38“ 4k TV instead, just make sure it has 60hz+ refresh rate

One of the issues is sharing your screen and aspect ratio.

You'll want a tiling window manager, depending on your OS

I prefer a single larger monitor; if I get absorbed by something "to the side" and gaze at it for 15 minutes, that's a recipe for neck/back problems.

One big monitor (curved or flat) + a tiling window manager.

3 non-curved. Easier to reorient them as needed (I have them in landscape by default most of the time but occassionally switch to portrait on one), built-in window management shortcuts, at least in Windows, to send windows to a different monitor, and snap to halves or quarters.

3 non-curved. Windows doesn't have an acceptable tiling solution for monitors yet; it always feels like a compromise. You can also change sources on one and plug it into something else and use two machines at the same time.