Yeah, it's better to use one emacs per project, and have less buffers open at a time. Not just the snappiness but a lot of the (out of the box, no special modes) keyboard buffer navigation stuff doesn't scale to hundreds of buffers. Maybe if I had better file naming conventions, but I tend to have a main.go in each cmd and sometimes even in pkg. I also rarely learn new modes/packages, as they aren't in on the VMs and so on that I also like to use emacs on.