I’d check if your hotend sits tight - it might be that it is not fully fixed and is pressed down by the filament. In other words: Check the grub screw that holds the hotend in place.
Aside from this, you may want to check your E-Steps (i.e. the number of stepper motor steps that are needed for a given amount of filament to be advanced - see here: Extruder Calibration a must). If you never did this, your toolhead would most likely UNDERextrude, not overextrude - so you only need to check if you ever messed with this value (but my be interested in doing the calibration at some point).
Also, check if you changed the flow rate in the slicer.
And final thought: Did you ever use abrasive filament like glow-in-the-dark or carbon fiber enforced? If so, your nozzle might be worn, i.e. have a too big hole, causing overextrusion.
Nothing else comes to my mind - anyone else ideas?