> On a 34" ultrawide monitor, it was too easy to put YouTube running on the left side, and whatever else on the right.
Yes, if you were doing that, almost any change to your environment that stops that will be good. I don't think you'd have to give up your monitor.
Switching to a non-ultrawide monitor might already have sufficed.
Yep, I just turn on the Leechblocker's lockdown mode which blocks all the distracting sites on my browser, I can focus on my work, without giving up any of my monitors, and all the advantages they provide me
Yeah, you can't blame the monitor setup for distractions.
Up to a point, more screen real-estate is a universally good thing. Although beyond, say, two 24-27" screens or one great big one, you get into rapidly diminishing returns.