My warped holes are driving me insane

I'm very new and love 3d printing but this is really driving twisting my private parts. It started when I tried printing parts to insert into other parts, they would never fit and the inner hole, square or whatever would be warped like in the pic. The pic is supposes to print out coin sizes for coins to fit through.

I have an Ender 3 and using Cura for splicing. I am presently sinking in a sea of bad tests and thinking I'm never going to get a good setting for this.

The settings I have changed (for various other problems with calibrations) are:

Print Temp 210, inner wall width .6, inner wall speed 30, inner wall acc 300, top layers 8, infill overlap percentahe 40, infill overlap .4, top surface layer 1, initial fan speed 25, regular fan speed 2, build plate temp 55, initial layer travel speed 50, skirt brim line width .3


If anyone could give me a hand on what I could possibly do to fix this it would be appreciated.

Sounds like your steps might not be right, or belts might be looses or pulleys might not be even. I mean it's an ender 3 - it's a piece of junk, you're going to have problems.

If you print a 20x10x3 mm oblong at 0.3mm layer height, what actual dimensions do you get ?
stl attached :-)

Also fan speed should either be 100% or none. There's not really any point pissing about with inbetween speeds. For PLA the first layer you want it off, so it sticks better: for all other layers you want it blowing as hard as it can. The quicker you cool the plastic the more accurate the print will be.

What surface are you printing on ?