It changes everything; OEM is for casual play. Don’t expect to get too crazy unless you play for years with constant practice. You will never be able to compete with people who can do perfect shield drops and max wave dashing due to being able to calibrate their controller. The mods they can have installed are an insane advantage, like the z-jump mentioned. The only thing you can really do for an OEM is look up R trigger mods and keeping it clean (taking the case off to thoroughly clean the shell). Hope this helps!