Lets take a look at Aespa and Blackpink.
On July 7th 2022, news was released that Aespa's new album broke 1,610,517 million preorders. They sold roughly 1,645,255 in their first month on Circle Chart. A roughly 35k album difference, not much difference in sales here.
Now Blackpink, on August 18th, roughly 6 days after announcement, BP surpassed 1.5 million preorders. Then a week later on the 25th it was announced that they passed 2 million preorders. BP physical album was released on September 16th, 2022. On the first month of Circle Chart it sold 2,457,206 copies. A roughly 400k difference. As you can seee, it is quite a large increase. though it must be noticed that there was roughly two weeks between the 2 million announcement for BP and their actual release. For Aespa, it was the day before the album was released. Thus BP did it quicker and had more time before the release to get more.
What does this mean for Twice? Twice announcement came out roughly 2 days before the release so I think it is likely to see an Aespa situation than a BP increase,. I would think that Twice's monthly sales might be around 1.8-1.9 million total as the album is released early in the month and people can buy the album throughout the month.
So I think it is unlikely Twice will pass 2 million in this release in the first month. Though I wouldn't be surprised if Im wrong as Twice always surprises us.