I too am a convert to small bags, though it’s easier now my kids are older and don’t need nappies/spare clothes/snacks on tap. If you have no extra capacity, it’s impossible to fill it with stuff and more incentive to clean out frequently. You sound like you need a bag rather than just a sleeve (though that would protect it) for your charger, but maybe if you got a bag-within-a-bag for the charger and other necessities, then you could restrict yourself to just that? It’s easier to organise stuff within a smaller internal bag. Or, you could put a see-through plastic bag into the laptop bag and any ‘extras’ go in there, that way it’s easy to pull out and dispose of extra stuff you don’t need if you happen to have put it in your laptop bag.