Remember none of this is confirmed, just speculation. This might be true or not.
One reason for this is that it has heat vision!
In the comics Doomsday is just a physical match for Superman and nothing else. So that's why he doesn't have any other powers other than punching. So heat vision is a no no. But it might not be heat vision but Omega Beams! So that's why they would be able to do this.
Because regular heat vision would be able to do this. Also we see batman Dogge it and we have seen batman doge it before.
We have seen supermans heat vision but it can't move
The 2nd reason is that it doesn't look much like doomsday.
If it was Doomsday it would have more spikes. It would look more like this.
One thing in common Doomsday and Darksied have in common they look like there made of rock.
This does kinda looks likes the creature we saw in the trailer.
The 3rd reason is that this might not be Doomsday's creation!
They change origins in movies all the time but this might not be Doomsdays origin. Lex Luther might have been trying to open a portal to apokolips.
Or lex is just trying to open a portal to get rid of superman through it then Darksied comes out and tires to kill everyone.