Well , he did said it was the fonts, haha. That's a very important thing. I remember I once added like 5000 fonts and hehe. That photoshop took like 2 mins to load up
well yes it can most certainly be fonts, the resolution can cause some freezing as well, but what i notice is that sometimes it can be a simple thing like the size of it, and that size you stated can easily be slowing down your PS b/c of the amount of RAM you have other than that idk just adding my cents in, hope they help
if it's fonts, why did it work well before? what i meant was the canvas resolution. when you make a new document, you need to choose height, width, resolution, and some other stuff.