Ironing flow test for your filaments.

How often the top layer that was ironed it's cracked or lines still visible ? No more failed top layers.

Specially with PETG you need to fine adjust the ironing flow to achieve the best results.

Presliced, just put your filament settings and your printer settings, all changes made by layer modifier.

First "test" its a Hilbert curve because it's cool and some filaments do very bad at this top pattern.