The only way I'd even *consider* mixing alu and copper without formal education in the topic is with a wago to keep them physically separated, with some "noalox" paste shoved down the hole. If it's alu to alu, a wire nut and some goop should be fine, but I don't trust my knowledge enough to have it directly touching copper, especially when it will be buried behind an appliance for 20 years.
2/2