My opinon on extra monitors

I agree with OP. I've only really "needed" a single 144 hz. My second monitor is 60 hz.
While it does feel much more "choppy" compared to the 144hz and the colors look kinda washed out in comparison, it does the job just fine.
I don't think I'll ever go back to single monitor either. this is just way too useful, especially when coding or learning something over YouTube/other resources.