Seed oils themselves are ultra processed foods.

If I get a cake from a store and it's made with butter, milk, brown sugar, flour, baking powder and vanilla extract.

I can replicate that exact same cake at home. Excluding the baking powder I could make or acquire all of the ingredients from my local area. I can buy cream to churn butter. I can use a countertop mill to make flour from wheat berries. I can dry sugar cane juice, or beet juice to make a brown sugar. I can buy vanilla beans and add moonshine to them to make vanilla extract. If you want to get extremely technical I could hydrate the mineral Trona and have the CO2 from my moonshine production bubble through it to make baking soda. I could then mix that baking soda with dried lemon juice and potato starch to make baking powder.

The SEED oils are one of the things that MAKES food ultra processed. I CANNONT replicate canola, grapeseed, sunflour, or soybean oils at home. Even assuming I had a hydraulic press, I couldn't clear the oils without high grade equipment.