Settings for a vertical tube

[swisscheese]

I've tried endless combinations in Cura to get a clean print on an oval shaped tube standing upright. The walls have 4 layers total. I'm running and Ender 3 Pro with SKR Mini 2.0 and PETG. I've had some prints with clean outside but never clean inside. I tried slowing down, changing hot end temp, combing, retraction, surface mode, arc welder, etc. I'm at my wit's end. Any suggestions? Here is my project file.

https://drive.google.com/file/d/15d3...ew?usp=sharing

PXL_20210916_100049032.jpg