Ender 3 pro seeing a lot of layer lines

I bought a used Ender 3 Pro that was in pretty bad shape a while back. I managed to restore it using (mostly) stock parts.

I took every precaution I could to make sure the entire frame was square by disassembling the entire printer and putting it back together with a square to ensure everything was aligned properly. I made sure the Z-lead screw sat inside the motor shaft straight. Luckily, it did, so I didn’t have to print any shims, motor mounts, or anything like that.

After getting everything back together and running, I printed a couple of test cubes that came out okay. Then, I decided to print a real model, which ended up being a Kirby model using the default Ender 3 Pro profile in Cura 5.9.

It looks okay, but I can see some layer lines that, after troubleshooting, I just can’t pin down. Nothing is binding or misaligned, and I only see a slight wobble in the lead screw—barely noticeable.

In these images I put primer on the model so you guys could see the layer lines better.

After troubleshooting and ensuring that nothing was binding or misaligned, I was stumped. I’m told on Reddit that this is ok quality for a (mostly) stock Ender 3 Pro and round models tend to show more layer lines anyway but I’d like your guy’s opinion on it.

If it helps here is a list of parts I did change on the printer as well as the troubleshooting I have done thus far.

Parts Changed:

  • Stock extruder arm was replaced with a dual-gear one.
  • Stock bed springs were replaced with the yellow compression springs.
  • Stock bowden tube was replaced with Capricorn version.
  • Both the hot end fan and the cooling fan had to be replaced as they were both dead. (I used stock fans for this).
  • Glass bed upgrade.
  • Added JST connectors to hot hot-end fan and cooling fan wires for easier maintenance

Troubleshooting:

  • I autotuned the PID for the hot end and the bed.
  • Calibrated e-steps.
  • Tightened X and Y belts.
  • Adjusted POM wheels on all X, Y, and Z axis
  • Adjusted the leadscrew nut screws (tried loosening and tightening them neither made much of a difference.)

I’m thinking of adding an upgrade which would probably be adding an Anti backlash POM nut and Oldham couplers to help mitigate this effect. But I’d like to hear any opinions or advice from you all. Is this ok quality for a mostly stock Ender 3 pro or is there something I’m missing here?