Here’s a weird truth: your sauce should look too thin in the pot. It should almost look like soup. Why? Because pasta absorbs liquid like a paper towel. It needs a bath, not a drizzle. If your sauce is thick in the pot, it will be a cement block in the oven.
Think of it like this: you are fattening the noodles from the inside out. Add an extra half cup of milk or cream. Throw in a splash of pasta water if you have it. The starch in that water is liquid gold. It keeps everything silky.