A greg's wade has enough ass to pull the filament in even if you use the makerfarm spool holder and it's a little sticky. Mine would only stop feeding when the filament was completely crossed up or pinchedand dead stopped from coming off the roll, and then in that case it would pull the x carriage off the nuts. I use 3mm. I now mount my spool on a bearing setup, but i put pretty decent pressure/tension on the roll so it can't freewheel, preventing the filament from getting loose and tangled or pinched.
The backpressure of the nozzle is a bigger factor. if the motor/extruder can't hold the filament down in the nozzle it is under backpressure and will relieve itself by slipping or skipping

Raise your temps. Hotter = easier to push out generally. at least, experiment with it.

tighten your idler. as long as you can run a piece of filament in and out easily by turning the wheel by hand (cold, filament not down all the way into the nozzle, motors off) it's not too tight imo. there should be teeth marks on the filament.

Make sure the teeth of your hobbed bolt are clean and not full of shredded plastic. dental pick can help there. Make sure when you look down the extruder the passages, hotend opening and notch in the hobbed bolt all line up.

Make sure you're slicing for the right nozzle diameter that you have.

make sure your idler bearing spins freely and doesn't have a flat spot somewhere - they are tight sometimes and the makerfarm idler print needs to be clearanced a bit. if the bearing is questionable rotate it to the bolt and bring a bearing from the bolt to the idler.

try different filament and see if one is problematic- maybe oversized or out of round.