Are you making everything from scratch?
It doesn't usually take 7 hours to make lasagna, does it?
If you make it right, from scratch, prep the dough: one kilo of flour for 10 eggs (Chef Claudio did 22) stir it with a machine if you can. By hand it's 45 minutes to get it right, sprinkle it with water, roll it into a ball, refrigerate overnight (i.e. let stand and proof). That's 1 1/2 hours of work max.
Stretch and cut the dough on Day 2, while you cook the meat at 80% of where it should be. Take the meat out, drain the fat, let it cool down for a few minutes. Oil the bottom of the lasagna dish.
Sauce: tomatoes? I like Roma. Boil so you can skin them and discard seeds easily. You can also do a bechamel to be the sauce. It's awesome with a nutty cheese. And you can do both. But cook it slow, don't burn it. One hour.
Assembly: you have the sauce, put some at the bottom of the dish, then lasagna, build layers with crumbles of a hard cheese in between. So that's maybe one hour.
Like 3 hours of work so far. The rest is watch and one intervention. "The Watch" begins: 45 minutes in a 380 degree (like 7 setting in France), take out and put that layer of cheese, Cook until it's brown on top and by then your nose will tell you everything that you need to know.
I couldn't help it...that's what I do!