Volume 12 sold 12,222 physical copies in its first week. That puts it just behind volume 10 and ahead of volume 11 in terms of first week sales. The digital sales of course aren’t accounted for, but it was a top seller a bookwalker for the first week.
If you’re interested in checking where it ranked in relation to other novels check the MAL link here to the weekly chart for April 2nd-8th.
I updated the sample translations with the first half of volume 8 chapter 1