The case might be a bit more difficult since you want the AND condition of the quantity, but you could utilize a few variables here.
What I recommend is creating a variable within the actual formula to retrieve the quantity and return a text value that sort of describes it. For example, you could add an IF condition that would return "Above5" if the quantity is above 5. For this, I'd recommend using nested IF statements over case.
Next you'd probably create a variable that would combine the SKU and quantity variable just mentioned. From there, you could create a case statement that would have a scenario for each. For example:
var text quantity = If([Quantity]>5,"Above5"[Quantity]<5,"Below5","")
var text combinedtext = [SKU]&"#"&$quantity;
var bool filtertest = Case($combinedtext,"ABC123#Above5",true,"ABC123#Below5"),true,false;
$filtertest
Although you may be able to use case here, it may be better to use some nested IF statements instead.
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William Knoll
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