As comparison with the VanillaTweaks iron bars on the right :

Same happen with the horizontal bars :

You can use VanillaTweaks (in the bottom Category of the website) fix bar as reference.
Honestly I like your classic model than the 3D one but it have Z fight as screenshot (i found the file in on your jar!).
Maybe you can add config option to choose between 3D and 2D in the config menu?
Thank you very much! (1.18.2)

@gamma1772 it is now vertical fixed but somewhat make the horizontal have Z-fight instead :

Uploaded 3.3.1 to GitHub releases, should fix this and #13

Uploaded 3.3.1 to GitHub releases, should fix this and #13
Work perfectly now, thank you!

Awesome!

@gamma1772 the Z fighting on classic vertical bar persist (horizontal fixed)

It also break bars from CreateDeco and other mods, all become iron :

resource pack you're currently using

I am using bar fix from VanillaTweak.

@gamma1772 the Z fighting on classic vertical bar persist (horizontal fixed)

I am unable to reproduce this issue, could it be due to the resource pack you're currently using, or some other mod?

I've published 3.2.0 on GitHub Releases, can you check if the z-flight still persists?
Additional Bars 3.2.0