Of course, it is always possible to take a jacket with 2 sizes above, but then everything is oversize, the sleeves, the hips, the collar ...
The air goes everywhere and above all it does not always give the most desired silhouette.
There is always the zip that cannot be closed because of the baby's head being carried and therefore the upper chest uncovered.
Once the babywearing period is over, we have a piece of clothing 2 sizes above that we have more reason to wear.