You can have room between the converter and flex plate, because the first place the converter will make contact if it's not all the way in is in the crank register. Take the transmission back off and put the converter in all the way.
This^^^^^^^^^^. The converter needs to go all the way into the transmission. I put a long bolt in one of the converter holes until it bottoms out (hand tight...you don’t need to impact the bolt in there) and then with my left hand on the converter I grab the bolt with my right hand and spin the converter. The light pressure with my left had will push the converter on to the pump lugs in the transmission.
You need those two square cut outs on the snout of the converter to go over the lugs in the pump. If you don’t get the converter all the way into the pump, it will likely kill the pump and maybe probably the thrust bearing. If you have my luck it will kill both of them.