I am using the Creality ender 3 v3 SE with eSuns PLA+ in black. The recommended printing temperature is 205-220 and I am printing at 210. The bed is set to 65°. When I print somewhat flat parts. The edges warp off the plate, while the printer is running and the plate is still hot. Until a few days ago it worked perfectly and I don’t know what I am doing different.
It is always only the first few layers, and the print never moves, so that the printer would make spaghetti, its just the edges that lift of a few millimeters.
Try the other suggestions, but something that has helped me is putting a thin layer of glue stick on my bed - stops the corners curling on larger prints