Cursor and keyboard are jittery and jumping across
Several keyboards and mouses I try that are wired or bluetooth keep actin erratically and jumping across the screen. both bluetooth and wired-- and several. i've tried reinstalling macOS and tried test user and it is system wide and very beyond annoying. the internal keyboard and trackpad work fine. i need the external keyboard and mouse because the screen is cracked and i use the mac in clamshell mode
your thoughts and insights to fix this?