That should work just fine, as long as it’s able to compress a bit and create a seal.

Another thing while you’re working on the hatch: air seal it as well. There are gasketed hatches, or you can install a stick-on gasket for the existing one. Stick it to the attic side (rather than the hatch). You may need to put a 2x2 frame inside the access if there’s not much space to stick to.

Air movement can carry a lot of moisture and thermal energy. Insulation isn’t very effective when air can just move through/around it.