Where are the passages to the storage spaces, and what do you want to use them for?
One is on the left in the room after the stairs and the other on the other side in the hallway.
I suspect insulation that no longer conforms to current standards. You can still leave it as it is, but you should then continue "similarly poorly" next to it to avoid creating thermal bridging gradients between adjacent areas.
I would actually like to redo the old insulation as well. What kind of material would be suitable for that?