I've heard some anecdotes that multiple monitors do reduce focus though[0]. I'm still on the fence though, the alternative to multiple monitors is often lots of workspaces, and switching between those can often feel just as jarring as looking to my left or right. Using i3, I often forget which workspace I left something on and spend 2 or 3 seconds cycling through every open workspace.

[0]: https://michael.stapelberg.ch/posts/2020-05-23-desk-setup/