Apple

For me size matters more than quantity. A lot of modern software is designed to have windows at least 24 inches wide and at that width you can't really fit four monitors on a desk. At 100 inches (horizontal not diagonal) you need to turn or roll your chair to see some of your windows.

So - at least one really big/wide monitor is the way to go in my opinion.

For that one I'd go with a Dell U4021QW - that's a 40" ultra wide that will comfortably support three or four large windows and more critically a single window with a bunch of internal sections. You really do need a curve at that size otherwise the left/right edge of the monitor is too far away.

You can also configure it as multiple virtual monitors, if you want for example the left half to be one computer and the right half to be another computer... or if your software just works better with multiple monitors you can make it into two monitors without any bezel separating them...

While it's nice and wide, it's not super tall... but I actually don't mind that. You need somewhere on your desk to put a glass of water, phone, etc without being in front of your monitor.

To get some height I'd go with two regular aspect ratio (and flat) 27" panels in portrait mode. Personally I'd go with Dell again - specifically the U2723QE which is a reasonably priced (for the quality) monitor with very small bezels. Rotated sideways and touching your desk at the bottom, it will be about as tall as you would ever want a monitor to be.

The middle panel will be 140ppi and the side panels 160ppi. That is not "retina" at laptop viewing distance (with the panel right next to your keyboard) but it is retina at a comfortable viewing distance for a monitor that large (at least 24in/60cm or so - personally mine is further away than that).

Finally, I recommend buying VESA arm mounts. Multi-arm mounts usually don't work well with a 40" panel (it might "work" but only if the panel is low to your desk) - so you're probably going to have to buy three single arms. It will free up loads of desk space (and you're going to be low on desk space), give you more flexibility to get the position/height/angle just right, and also be more stable than the stand that comes with any of those monitors.

Make sure the one for your 40" panel in particular can handle that much weight. I'd go for one that is advertised as handling quite a bit more weight than what you're putting on it. Less of an issue for the side monitors since I'd have those resting on your desk.