In BtN, it's explicitly stated that Nero lost quickly because he only had one arm and wasn't used to fighting like that.
I don't think you realized but what Nero is talking about, which also happens in the manga, is that because he doesn't have his arm he can't defend properly... which still doesn't matter because he literally got one shoted. If Urizen was playing he wouldn't have instantly rekt Nero, like you say he would have "played and toyed" but he didn't do that.
In the second fight, he managed to hold out long enough to land a hit, and Urizen was somewhat surprised.
We all know the second fight is full of plot armor and outliers, using it as a legit argument just doesn't work.
This proves that Urizen was never truly committed and serious until he finally got off his throne.
Nope
The fight takes place off-screen, but we hear it in the mission where Dante is playing as he heads towards Urizen. This means that Urizen didn't instantly one-shot them.
We are told what their plan was and why it failed. Lady does support from behind with guns and Trish rushes with the Sparda but it failed because the moment the rockets hit the shield the shockwave stopped everything and put Trish out of commission while Lady being far behind didn't get hit completely.
They even try it again and same thing happens, even when Trish uses Artemis as a last resort.
There was no fight, no conflict, Urizen was just chilling and the duo just crashed against the Yamato shield like a car going at 180 mph against a building hoping to make it past the first wall but exploding against the tree in front of it.
Also, we went way off topic here. Point is, Urizen wasn't toying, hell he only becomes stronger than Dante when Nero is already inside the tree as seen in the manga.
Also, don't forget one very important part, its explicitly said in the nico report that Urizen wasn't fighting sitting on the throne out of contempt, he needed to stay seated and rooted on the Qliphoth to grow stronger and absorb power (probably on life support just like how Dante was on life support for the whole month)
If Urizen got up not only he would stop getting power which means Dante would become stronger but also would start dying out.
I only discussed this with you and no one else.
Pretty sure there were like 8 dudes jumping you to the point some of us stopped arguing because it was too much.