I've had bad luck with top entrances. I lost more than one hive because the queen moved up into the supers and the hive abandoned the brood down below which caused AFB.
Abandon brood near bottom?
Long time ago I looked what happens when I enlarged by putting new box over brood box. I noticed that bees were not able to keep warm lowest larvae and they ate a lot them away. Part of lowest capped pupae died.
Same happens when I put bottom entrance wide open. Lowest brood get cold.
Third way is to keep too many holes open in upper boxes.
Fourth is to put empty frame in the middle of brood area and so on.
Violent enlargement of brood area is serius question for 1-box and even 2-box hive.
If hive has brood in lowest box, I prefer to open middle entrances than put low entrance totally open for ventilation. If I need maximun ventilation on canola field, I put entra box lowest. It is vety handy for foraging bees. Otherwise they may hang ovenight on outside of hive.
I check ventilation from the number of ventilating bees.