The news is not exactly accurate in the sense that the producer is Kashiwada, not Miki who is just the Dengeki editor.
It was Kashiwada who wanted to cover the entire Alicization arc. Also, it is a punishment leak for an on-screen game in the stream, so I won't go as far as to say it is an ultimate confirmation. The chances are very very high but we don't know.
There is going to be a chance for it to be rushed. Kashiwada is also the producer in charge of Grancrest Senki, which got the insane rush-fuck going on now (one of the volumes was covered in one episode), because he wanted to reach the latest climax point in the series (volume 9-10).
Akasaki also asked how many cours but it wasn't revealed. So maybe it won't be just two-cour. But I won't be surprised if it is just two-cour, given what Kashiwada had been up to lately with his adaptations.
https://youtu.be/n8DDzqZ7bBk?t=2564
There's going to be some announcement next week.