Sure anything you can do yourself on the website/app you should. But if it's something you couldn't do ahead of time, like set your UDP selections, the concierge should help with this before you board.
If you want to dress up, you don't need a formal night to do that.
If you don't want to dress up, then that's fine, just wear what you want on formal night like many others will.
Jewel right now is a "premium" route which has a tendency to attract more high level C&A numbers. I would imagine the restriction kicks in more often on those long/lean type routes instead of the weekenders or the standard 7 night Caribbean
For the purposes of the OP's question, no ship has self service laundry, even if one ship sailing one very unique itinerary has them temporarily for a subset of passengers.
I've had those. One went to the crew mess to find a certain flavor of PowerAde for my son that wasn't in any of the public bars. On top of making sure there was a certain type of bourbon there for me.
He was well taken care of that week as a result.
The only issue is how well stocked the bartender wants to be. I've seen the old school "suite bar menu" with like 3 things on it, and I've seen 20+ bottles of liquor brought in each night.