I'm curious, how do you think this helps you answer the question? Proxies are incredibly easy to come by these days, rotation makes it hard to identify what's behind it all.
My favorite ISP to spot occasionally is SpaceX / Starlink. That can’t be the most economical ISP for bot traffic, but machines can be infected, even on Starlink.
And I remember more than a decade ago I went down the rabbit hole hunting these bots and indeed, I found Netherlands was always the king of hill when it comes to bots, followed by US, Netherlands still there I see.
One of my favorite visualizations for this is to switch to the globe view and choose the “HEAT” style for a 3D heatmap superimposed on the globe. Green means few hits, and red signifies lots of hits. The Netherlands is so small that it’s tough to see though!