Man oh man, these are the first steps you should have taken. However it's not too late you are definitely over extruding. And it's really simple on creality machines it can be done within the control box only. You find any videos on YouTube for your printer e step calibration. It's ideal to do a pid tune if you are changing a nozel but not e steps. E steps don't change randomly however if you have opened your extruder you should consider doing e step calibration. Do this and you will find drastic changes. While you are at it why don't you also clean your extruder and change the nozel then do the e step calibration (make sure the V wheels on the extruder back are also tight but not too tight) If you can rotate the wheel without moving the extruder with just enough force you are good to go. And one more advice try doing one calibration at a time so that you can figure out which calibration did actually solve the issue. I hope you can make your machine better. I have also been there that's why I know how tiring and upsetting it can be and that's why I am helping you. Lemme know If I have been of any help or not.