I'm sorry you're finding it so challenging, and especially over special family holidays it can be rough. Here are some strategies that I've used. (Also, I'm single, no kid, so I'm not cooking for anyone else.) Are you trying to have your kid also be whole 30 (it might be too challenging at this point.)?
What are your goals/motivation for doing the Whole30? Keep those in mind.
If you make soup, make some extra and freeze it for future meals.
Same with casseroles/egg bakes type thing.
I don't suffer from food boredom and I don't need something new everyday, so I'm a huge leftover fan.
I'll often roast a tray of veggies on my top oven tray, bake a tray of meatballs at the same time on my bottom oven tray. While eating those for dinner, I'll have two more trays going for leftovers. One time cooking, multiple meals.
Depending on grocery stores in your area, rotisserie chickens can be available with only compliant ingredients, but watch your labels.
Your meals don't have to be instagram-worthy or even look like someone else's idea of a complete meal.
It also depends on what type of resources you have at work/home, but assuming a freezer and microwave:
A package of frozen vegetables, some coconut milk, some canned chicken or salmon: Microwave for 5 minutes, add salt and pepper: Easy delicious soup!
I've done some sauteed onions, add a can of diced tomatoes and a can of tuna, simmer until hot: Easy meal. Can top with some olives.
Things I often use for traveling, no refrigeration or prep: package or can of salmon, some baby foods of sweet potato puree. (Ideal? No. Do-able? Yes.)
Yes, rotisserie and canned foods can be more expensive, but they are far less expensive than dining out. Always read labels!
Somewhere along the way I bookmarked this thread: