Dark roast coffee beans are almost always oily and they are very bad for a full automatic expresso machine.
We buy only medium roast beans (mostly Lavazza) for our full automatic Delonghi expresso machine.
I see you are from BC. Did you try Kicking Horse coffee (
https://www.kickinghorsecoffee.com/) ?
Kicking Horse is a company from BC. Their coffee beans are certified Organic and Fairtrade, which come from many places around the world and roasted in BC.
We like their Smart Ass and their Cliff Hanger Expresso beans but Costco doesn't sell any Kicking Horse coffee beans and thus they are more expensive to buy at the grocery store than the Lavazza coffee beans at Costco.