All of the work involved in meals is easily the most discouraging task in my week. Planning, shopping, cooking, cleaning up, doing it all again the next day, hearing all of the complaints, trying to pick meals that aren't boring but aren't too much work but are nutritious while also being something most of the kids will probably eat - I hear you. It's exhausting.
I lessen the burden a bit by having each person choose one meal (so I have to plan less) - but then they tend to each pick their favourite meal every week, so that doesn't always work very well. I have my oldest cook one meal each week, and DH usually does at least one meal per week, so that also helps. When they leave the dinner table, they each take their dishes plus one other thing. No one eats in the living room, but mine are younger than yours so I'll bet that's a lot easier for me to enforce for now.
I don't know. All the usual tips, but it really doesn't make the whole process any less discouraging. I told DH tonight that I was just going to outsource dinners because I just can't anymore. He didn't seem to think that would be very economical.
And the kitchen thing does make I huge difference. One of our houses had a very narrow kitchen, no wider than a hallway, and I hated cooking with a passion the whole time we lived there. Our next kitchen was much more open and it made an incredible difference in how I felt about making meals.
Sorry no help, just commiseration.