Why do you even need 3 monitors? That seems excessive.
If you are doing web dev, it's literally a must. One screen to type code, one screen for the browser, and one screen for the browser webdev tools. Sometimes I wish I have a forth screen for the documentation.
Put the browser on screen two. Put your IDE and Dev tools on the main monitor. You aren’t really going to operate your IDE and the dev tools at exactly the same time. So you can write your code, flip to the browser, test and inspect your changes, and flip back when it doesn’t work.
I have two monitors and my laptop screen, which is really 2.5 monitors. Since I upgraded one of the screens to a 27 inch, the real estate difference between that monitor and my laptop is so stark that I resist using the laptop screen at all. I really only use all three in a handful of situations.
Screen juggling gets non-trivial when the work I’m doing involves command line tools with behavior showing up in a UI - either our UI, or our infrastructure (eg, modifying a build script that is breaking only in CI).
Occasionally I have to keep a semi-active eye on our production stats while also progressing on other work. But only about 10% of the people in our program have to do that work, and we tend to tag team. I could almost do that work by bringing a tablet into the mix.
But even still, the third screen would barely be necessary if I wasn’t taking little breaks all the time to do other work, like research, or to blow off steam on HN. My windows begin to get mixed up and hunting the right one down gets more complicated.