Anyone used a carrier for bigger infants/toddlers that they loved?

Background: we commute via subway and walking. Stroller is not an option due to elevator outages and crowds. I have a large osprey daypack on my back with bottles/daycare food/pump stuff/my lunch/laptop/etc that weighs like a brick, and then there is my 25 + pound 9 month old. I'm using the lillebaby with him facing in on the front (facing out nearly broke my back), but am just wondering if this is as good as it's going to get (ouch my shoulders) or if there's anything else that's good for carrying a heavy kid. I don't even want to think how big he's going to be before he doesn't need to be carried anymore. Thank you!