If you purchase genuine free range eggs from a farm that feeds there hens on good quality feed, the eggs never crack when boiled, supermarkets that claim free range eggs are normally kept in a barn, grossly overcrowded and to keep prices down are fed on a relatively poor diet which is why the shells are thin and weak
I have a rice cooker where the lid's vent hole is slightly too small, so I've done this by propping the lid open with a chopstick on one end of the lid. If you want it to be evenly vented, you could put one chopstick on both sides of the lid.
Funny enough, I saw a little silicone gadget the other day when I was out shopping - those stick men called Lid Sid are designed to do exactly what you want. Granted, they are real unitaskers, but also kind of fun.
Other manufacturers make similar items in other shapes - I have seen sheep, witches and others.
If you were doing this a lot it might be worth making a little thing with an H shaped cross section (like a bit of a girder), one pair of legs straddle the rim of the pan and the lid rests on the others. You could make it asymmetric to get variable heights. You'd have to consider the material carefully, i.e. no metal if it's to go in a microwave, some woods ...
Tilt the lid.
It will stay where you put it… approximately.
See pan top left & pyrex bottom right; they will stay like that all day if needed
If it really refuses to stay, then wedge a spatula [or any other bit of wood or plastic (& of course, not metal if it's going in the microwave) of any appropriate size]* in it, either from the edge, down the ...
Just cook the pasta a couple minutes later. I can't think of a sauce that couldn't sit there for a couple of minutes while the pasta finishes, should you mess up the timing. Even reduced cream sauces, you can always add a little pasta water should the sauec over-thicken.