I've just built and started printing with my Ender 3 v2 and everything I print is roughly 20% smaller than it should be, it's the same in PRUSA, CURA and the Creality Version too. The belts are NOT slipping. it's got 20 tooth pulleys and if I move the X 40mm it's 1 revolution of the stepper, so everything seems to be working. there is NO scaling and I've also tried changing the transmission ratio on X and Y from 80 to 100, this prints closer to expected size as you can see here https://imgur.com/r0lD446 but the print quality is bad. Also the firmware is 1.0.2 so it's all up to date.
please can someone help, it's REALLY frustrating, there a some shots to explain what I'm talking about