Toby
I also have a 2018 Elite II.
My procedure may not help you. But, after the Ollie wakes up from it winter's nap, I have trouble getting the Dometic refigerator started. I usually have to play with the on-off switch button, depressing the button multiple times and sometimes just holding the button in. So far, after a little time doing this the refrigerator finally starts and the lights on the control board come on.
On another subject, in the future, you might want to add your year and hull # to the signature line, so people can see what Ollie you have and can help you better.